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 <unistd.h>
34 #include <fcntl.h>
35 #include <sys/wait.h>
36
37 static const char *pname = "tc-ipt";
38 static const char *tname = "mangle";
39 static const char *pversion = "0.1";
40
41 static const char *ipthooks[] = {
42 "NF_IP_PRE_ROUTING",
43 "NF_IP_LOCAL_IN",
44 "NF_IP_FORWARD",
45 "NF_IP_LOCAL_OUT",
46 "NF_IP_POST_ROUTING",
47 };
48
49 static struct option original_opts[] = {
50 {"jump", 1, 0, 'j'},
51 {0, 0, 0, 0}
52 };
53
54 static struct iptables_target *t_list = NULL;
55 static struct option *opts = original_opts;
56 static unsigned int global_option_offset = 0;
57 #define OPTION_OFFSET 256
58
59 char *lib_dir;
60
61 void
register_target(struct iptables_target * me)62 register_target(struct iptables_target *me)
63 {
64 /* fprintf(stderr, "\nDummy register_target %s \n", me->name);
65 */
66 me->next = t_list;
67 t_list = me;
68
69 }
70
71 void
xtables_register_target(struct iptables_target * me)72 xtables_register_target(struct iptables_target *me)
73 {
74 me->next = t_list;
75 t_list = me;
76 }
77
78 void
exit_tryhelp(int status)79 exit_tryhelp(int status)
80 {
81 fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
82 pname, pname);
83 exit(status);
84 }
85
86 void
exit_error(enum exittype status,char * msg,...)87 exit_error(enum exittype status, char *msg, ...)
88 {
89 va_list args;
90
91 va_start(args, msg);
92 fprintf(stderr, "%s v%s: ", pname, pversion);
93 vfprintf(stderr, msg, args);
94 va_end(args);
95 fprintf(stderr, "\n");
96 if (status == PARAMETER_PROBLEM)
97 exit_tryhelp(status);
98 if (status == VERSION_PROBLEM)
99 fprintf(stderr,
100 "Perhaps iptables or your kernel needs to be upgraded.\n");
101 exit(status);
102 }
103
104 /* stolen from iptables 1.2.11
105 They should really have them as a library so i can link to them
106 Email them next time i remember
107 */
108
109 char *
addr_to_dotted(const struct in_addr * addrp)110 addr_to_dotted(const struct in_addr *addrp)
111 {
112 static char buf[20];
113 const unsigned char *bytep;
114
115 bytep = (const unsigned char *) &(addrp->s_addr);
116 sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
117 return buf;
118 }
119
string_to_number_ll(const char * s,unsigned long long min,unsigned long long max,unsigned long long * ret)120 int string_to_number_ll(const char *s, unsigned long long min,
121 unsigned long long max,
122 unsigned long long *ret)
123 {
124 unsigned long long number;
125 char *end;
126
127 /* Handle hex, octal, etc. */
128 errno = 0;
129 number = strtoull(s, &end, 0);
130 if (*end == '\0' && end != s) {
131 /* we parsed a number, let's see if we want this */
132 if (errno != ERANGE && min <= number && (!max || number <= max)) {
133 *ret = number;
134 return 0;
135 }
136 }
137 return -1;
138 }
139
string_to_number_l(const char * s,unsigned long min,unsigned long max,unsigned long * ret)140 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
141 unsigned long *ret)
142 {
143 int result;
144 unsigned long long number;
145
146 result = string_to_number_ll(s, min, max, &number);
147 *ret = (unsigned long)number;
148
149 return result;
150 }
151
string_to_number(const char * s,unsigned int min,unsigned int max,unsigned int * ret)152 int string_to_number(const char *s, unsigned int min, unsigned int max,
153 unsigned int *ret)
154 {
155 int result;
156 unsigned long number;
157
158 result = string_to_number_l(s, min, max, &number);
159 *ret = (unsigned int)number;
160
161 return result;
162 }
163
free_opts(struct option * local_opts)164 static void free_opts(struct option *local_opts)
165 {
166 if (local_opts != original_opts) {
167 free(local_opts);
168 opts = original_opts;
169 global_option_offset = 0;
170 }
171 }
172
173 static struct option *
merge_options(struct option * oldopts,const struct option * newopts,unsigned int * option_offset)174 merge_options(struct option *oldopts, const struct option *newopts,
175 unsigned int *option_offset)
176 {
177 struct option *merge;
178 unsigned int num_old, num_new, i;
179
180 for (num_old = 0; oldopts[num_old].name; num_old++) ;
181 for (num_new = 0; newopts[num_new].name; num_new++) ;
182
183 *option_offset = global_option_offset + OPTION_OFFSET;
184
185 merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
186 memcpy(merge, oldopts, num_old * sizeof (struct option));
187 for (i = 0; i < num_new; i++) {
188 merge[num_old + i] = newopts[i];
189 merge[num_old + i].val += *option_offset;
190 }
191 memset(merge + num_old + num_new, 0, sizeof (struct option));
192
193 return merge;
194 }
195
196 static void *
fw_calloc(size_t count,size_t size)197 fw_calloc(size_t count, size_t size)
198 {
199 void *p;
200
201 if ((p = (void *) calloc(count, size)) == NULL) {
202 perror("iptables: calloc failed");
203 exit(1);
204 }
205 return p;
206 }
207
208 static struct iptables_target *
find_t(char * name)209 find_t(char *name)
210 {
211 struct iptables_target *m;
212 for (m = t_list; m; m = m->next) {
213 if (strcmp(m->name, name) == 0)
214 return m;
215 }
216
217 return NULL;
218 }
219
220 static struct iptables_target *
get_target_name(const char * name)221 get_target_name(const char *name)
222 {
223 void *handle;
224 char *error;
225 char *new_name, *lname;
226 struct iptables_target *m;
227 char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
228
229 #ifdef NO_SHARED_LIBS
230 return NULL;
231 #endif
232
233 new_name = malloc(strlen(name) + 1);
234 lname = malloc(strlen(name) + 1);
235 if (new_name)
236 memset(new_name, '\0', strlen(name) + 1);
237 else
238 exit_error(PARAMETER_PROBLEM, "get_target_name");
239
240 if (lname)
241 memset(lname, '\0', strlen(name) + 1);
242 else
243 exit_error(PARAMETER_PROBLEM, "get_target_name");
244
245 strcpy(new_name, name);
246 strcpy(lname, name);
247
248 if (isupper(lname[0])) {
249 int i;
250 for (i = 0; i < strlen(name); i++) {
251 lname[i] = tolower(lname[i]);
252 }
253 }
254
255 if (islower(new_name[0])) {
256 int i;
257 for (i = 0; i < strlen(new_name); i++) {
258 new_name[i] = toupper(new_name[i]);
259 }
260 }
261
262 /* try libxt_xx first */
263 sprintf(path, "%s/libxt_%s.so", lib_dir, new_name);
264 handle = dlopen(path, RTLD_LAZY);
265 if (!handle) {
266 /* try libipt_xx next */
267 sprintf(path, "%s/libipt_%s.so", lib_dir, new_name);
268 handle = dlopen(path, RTLD_LAZY);
269
270 if (!handle) {
271 sprintf(path, "%s/libxt_%s.so", lib_dir , lname);
272 handle = dlopen(path, RTLD_LAZY);
273 }
274
275 if (!handle) {
276 sprintf(path, "%s/libipt_%s.so", lib_dir , lname);
277 handle = dlopen(path, RTLD_LAZY);
278 }
279 /* ok, lets give up .. */
280 if (!handle) {
281 fputs(dlerror(), stderr);
282 printf("\n");
283 free(new_name);
284 return NULL;
285 }
286 }
287
288 m = dlsym(handle, new_name);
289 if ((error = dlerror()) != NULL) {
290 m = (struct iptables_target *) dlsym(handle, lname);
291 if ((error = dlerror()) != NULL) {
292 m = find_t(new_name);
293 if (NULL == m) {
294 m = find_t(lname);
295 if (NULL == m) {
296 fputs(error, stderr);
297 fprintf(stderr, "\n");
298 dlclose(handle);
299 free(new_name);
300 return NULL;
301 }
302 }
303 }
304 }
305
306 free(new_name);
307 return m;
308 }
309
310
dotted_to_addr(const char * dotted)311 struct in_addr *dotted_to_addr(const char *dotted)
312 {
313 static struct in_addr addr;
314 unsigned char *addrp;
315 char *p, *q;
316 unsigned int onebyte;
317 int i;
318 char buf[20];
319
320 /* copy dotted string, because we need to modify it */
321 strncpy(buf, dotted, sizeof (buf) - 1);
322 addrp = (unsigned char *) &(addr.s_addr);
323
324 p = buf;
325 for (i = 0; i < 3; i++) {
326 if ((q = strchr(p, '.')) == NULL)
327 return (struct in_addr *) NULL;
328
329 *q = '\0';
330 if (string_to_number(p, 0, 255, &onebyte) == -1)
331 return (struct in_addr *) NULL;
332
333 addrp[i] = (unsigned char) onebyte;
334 p = q + 1;
335 }
336
337 /* we've checked 3 bytes, now we check the last one */
338 if (string_to_number(p, 0, 255, &onebyte) == -1)
339 return (struct in_addr *) NULL;
340
341 addrp[3] = (unsigned char) onebyte;
342
343 return &addr;
344 }
345
set_revision(char * name,u_int8_t revision)346 static void set_revision(char *name, u_int8_t revision)
347 {
348 /* Old kernel sources don't have ".revision" field,
349 * but we stole a byte from name. */
350 name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
351 name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
352 }
353
354 /*
355 * we may need to check for version mismatch
356 */
357 int
build_st(struct iptables_target * target,struct ipt_entry_target * t)358 build_st(struct iptables_target *target, struct ipt_entry_target *t)
359 {
360 unsigned int nfcache = 0;
361
362 if (target) {
363 size_t size;
364
365 size =
366 IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
367
368 if (NULL == t) {
369 target->t = fw_calloc(1, size);
370 target->t->u.target_size = size;
371
372 if (target->init != NULL)
373 target->init(target->t, &nfcache);
374 set_revision(target->t->u.user.name, target->revision);
375 } else {
376 target->t = t;
377 }
378 strcpy(target->t->u.user.name, target->name);
379 return 0;
380 }
381
382 return -1;
383 }
384
parse_ipt(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)385 static int parse_ipt(struct action_util *a,int *argc_p,
386 char ***argv_p, int tca_id, struct nlmsghdr *n)
387 {
388 struct iptables_target *m = NULL;
389 struct ipt_entry fw;
390 struct rtattr *tail;
391 int c;
392 int rargc = *argc_p;
393 char **argv = *argv_p;
394 int argc = 0, iargc = 0;
395 char k[16];
396 int res = -1;
397 int size = 0;
398 int iok = 0, ok = 0;
399 __u32 hook = 0, index = 0;
400 res = 0;
401
402 lib_dir = getenv("IPTABLES_LIB_DIR");
403 if (!lib_dir)
404 lib_dir = IPT_LIB_DIR;
405
406 {
407 int i;
408 for (i = 0; i < rargc; i++) {
409 if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
410 break;
411 }
412 }
413 iargc = argc = i;
414 }
415
416 if (argc <= 2) {
417 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
418 return -1;
419 }
420
421 while (1) {
422 c = getopt_long(argc, argv, "j:", opts, NULL);
423 if (c == -1)
424 break;
425 switch (c) {
426 case 'j':
427 m = get_target_name(optarg);
428 if (NULL != m) {
429
430 if (0 > build_st(m, NULL)) {
431 printf(" %s error \n", m->name);
432 return -1;
433 }
434 opts =
435 merge_options(opts, m->extra_opts,
436 &m->option_offset);
437 } else {
438 fprintf(stderr," failed to find target %s\n\n", optarg);
439 return -1;
440 }
441 ok++;
442 break;
443
444 default:
445 memset(&fw, 0, sizeof (fw));
446 if (m) {
447 m->parse(c - m->option_offset, argv, 0,
448 &m->tflags, NULL, &m->t);
449 } else {
450 fprintf(stderr," failed to find target %s\n\n", optarg);
451 return -1;
452
453 }
454 ok++;
455 break;
456
457 }
458 }
459
460 if (iargc > optind) {
461 if (matches(argv[optind], "index") == 0) {
462 if (get_u32(&index, argv[optind + 1], 10)) {
463 fprintf(stderr, "Illegal \"index\"\n");
464 free_opts(opts);
465 return -1;
466 }
467 iok++;
468
469 optind += 2;
470 }
471 }
472
473 if (!ok && !iok) {
474 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
475 return -1;
476 }
477
478 /* check that we passed the correct parameters to the target */
479 if (m)
480 m->final_check(m->tflags);
481
482 {
483 struct tcmsg *t = NLMSG_DATA(n);
484 if (t->tcm_parent != TC_H_ROOT
485 && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
486 hook = NF_IP_PRE_ROUTING;
487 } else {
488 hook = NF_IP_POST_ROUTING;
489 }
490 }
491
492 tail = NLMSG_TAIL(n);
493 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
494 fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
495 fprintf(stdout, "\ttarget: ");
496
497 if (m)
498 m->print(NULL, m->t, 0);
499 fprintf(stdout, " index %d\n", index);
500
501 if (strlen(tname) > 16) {
502 size = 16;
503 k[15] = 0;
504 } else {
505 size = 1 + strlen(tname);
506 }
507 strncpy(k, tname, size);
508
509 addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
510 addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
511 addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
512 if (m)
513 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
514 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
515
516 argc -= optind;
517 argv += optind;
518 *argc_p = rargc - iargc;
519 *argv_p = argv;
520
521 optind = 0;
522 free_opts(opts);
523 /* Clear flags if target will be used again */
524 m->tflags=0;
525 m->used=0;
526 /* Free allocated memory */
527 if (m->t)
528 free(m->t);
529
530
531 return 0;
532
533 }
534
535 static int
print_ipt(struct action_util * au,FILE * f,struct rtattr * arg)536 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
537 {
538 struct rtattr *tb[TCA_IPT_MAX + 1];
539 struct ipt_entry_target *t = NULL;
540
541 if (arg == NULL)
542 return -1;
543
544 lib_dir = getenv("IPTABLES_LIB_DIR");
545 if (!lib_dir)
546 lib_dir = IPT_LIB_DIR;
547
548 parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
549
550 if (tb[TCA_IPT_TABLE] == NULL) {
551 fprintf(f, "[NULL ipt table name ] assuming mangle ");
552 } else {
553 fprintf(f, "tablename: %s ",
554 (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
555 }
556
557 if (tb[TCA_IPT_HOOK] == NULL) {
558 fprintf(f, "[NULL ipt hook name ]\n ");
559 return -1;
560 } else {
561 __u32 hook;
562 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
563 fprintf(f, " hook: %s \n", ipthooks[hook]);
564 }
565
566 if (tb[TCA_IPT_TARG] == NULL) {
567 fprintf(f, "\t[NULL ipt target parameters ] \n");
568 return -1;
569 } else {
570 struct iptables_target *m = NULL;
571 t = RTA_DATA(tb[TCA_IPT_TARG]);
572 m = get_target_name(t->u.user.name);
573 if (NULL != m) {
574 if (0 > build_st(m, t)) {
575 fprintf(stderr, " %s error \n", m->name);
576 return -1;
577 }
578
579 opts =
580 merge_options(opts, m->extra_opts,
581 &m->option_offset);
582 } else {
583 fprintf(stderr, " failed to find target %s\n\n",
584 t->u.user.name);
585 return -1;
586 }
587 fprintf(f, "\ttarget ");
588 m->print(NULL, m->t, 0);
589 if (tb[TCA_IPT_INDEX] == NULL) {
590 fprintf(f, " [NULL ipt target index ]\n");
591 } else {
592 __u32 index;
593 index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
594 fprintf(f, " \n\tindex %d", index);
595 }
596
597 if (tb[TCA_IPT_CNT]) {
598 struct tc_cnt *c = RTA_DATA(tb[TCA_IPT_CNT]);;
599 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
600 }
601 if (show_stats) {
602 if (tb[TCA_IPT_TM]) {
603 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
604 print_tm(f,tm);
605 }
606 }
607 fprintf(f, " \n");
608
609 }
610 free_opts(opts);
611
612 return 0;
613 }
614
615 struct action_util ipt_action_util = {
616 .id = "ipt",
617 .parse_aopt = parse_ipt,
618 .print_aopt = print_ipt,
619 };
620
621