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 free(lname);
285 return NULL;
286 }
287 }
288
289 m = dlsym(handle, new_name);
290 if ((error = dlerror()) != NULL) {
291 m = (struct iptables_target *) dlsym(handle, lname);
292 if ((error = dlerror()) != NULL) {
293 m = find_t(new_name);
294 if (NULL == m) {
295 m = find_t(lname);
296 if (NULL == m) {
297 fputs(error, stderr);
298 fprintf(stderr, "\n");
299 dlclose(handle);
300 free(new_name);
301 free(lname);
302 return NULL;
303 }
304 }
305 }
306 }
307
308 free(new_name);
309 free(lname);
310 return m;
311 }
312
313
dotted_to_addr(const char * dotted)314 struct in_addr *dotted_to_addr(const char *dotted)
315 {
316 static struct in_addr addr;
317 unsigned char *addrp;
318 char *p, *q;
319 unsigned int onebyte;
320 int i;
321 char buf[20];
322
323 /* copy dotted string, because we need to modify it */
324 strncpy(buf, dotted, sizeof (buf) - 1);
325 addrp = (unsigned char *) &(addr.s_addr);
326
327 p = buf;
328 for (i = 0; i < 3; i++) {
329 if ((q = strchr(p, '.')) == NULL)
330 return (struct in_addr *) NULL;
331
332 *q = '\0';
333 if (string_to_number(p, 0, 255, &onebyte) == -1)
334 return (struct in_addr *) NULL;
335
336 addrp[i] = (unsigned char) onebyte;
337 p = q + 1;
338 }
339
340 /* we've checked 3 bytes, now we check the last one */
341 if (string_to_number(p, 0, 255, &onebyte) == -1)
342 return (struct in_addr *) NULL;
343
344 addrp[3] = (unsigned char) onebyte;
345
346 return &addr;
347 }
348
set_revision(char * name,u_int8_t revision)349 static void set_revision(char *name, u_int8_t revision)
350 {
351 /* Old kernel sources don't have ".revision" field,
352 * but we stole a byte from name. */
353 name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
354 name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
355 }
356
357 /*
358 * we may need to check for version mismatch
359 */
360 int
build_st(struct iptables_target * target,struct ipt_entry_target * t)361 build_st(struct iptables_target *target, struct ipt_entry_target *t)
362 {
363 unsigned int nfcache = 0;
364
365 if (target) {
366 size_t size;
367
368 size =
369 IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
370
371 if (NULL == t) {
372 target->t = fw_calloc(1, size);
373 target->t->u.target_size = size;
374
375 if (target->init != NULL)
376 target->init(target->t, &nfcache);
377 set_revision(target->t->u.user.name, target->revision);
378 } else {
379 target->t = t;
380 }
381 strcpy(target->t->u.user.name, target->name);
382 return 0;
383 }
384
385 return -1;
386 }
387
parse_ipt(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)388 static int parse_ipt(struct action_util *a,int *argc_p,
389 char ***argv_p, int tca_id, struct nlmsghdr *n)
390 {
391 struct iptables_target *m = NULL;
392 struct ipt_entry fw;
393 struct rtattr *tail;
394 int c;
395 int rargc = *argc_p;
396 char **argv = *argv_p;
397 int argc = 0, iargc = 0;
398 char k[16];
399 int size = 0;
400 int iok = 0, ok = 0;
401 __u32 hook = 0, index = 0;
402
403 lib_dir = getenv("IPTABLES_LIB_DIR");
404 if (!lib_dir)
405 lib_dir = IPT_LIB_DIR;
406
407 {
408 int i;
409 for (i = 0; i < rargc; i++) {
410 if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
411 break;
412 }
413 }
414 iargc = argc = i;
415 }
416
417 if (argc <= 2) {
418 fprintf(stderr,"bad arguments to ipt %d vs %d \n", argc, rargc);
419 return -1;
420 }
421
422 while (1) {
423 c = getopt_long(argc, argv, "j:", opts, NULL);
424 if (c == -1)
425 break;
426 switch (c) {
427 case 'j':
428 m = get_target_name(optarg);
429 if (NULL != m) {
430
431 if (0 > build_st(m, NULL)) {
432 printf(" %s error \n", m->name);
433 return -1;
434 }
435 opts =
436 merge_options(opts, m->extra_opts,
437 &m->option_offset);
438 } else {
439 fprintf(stderr," failed to find target %s\n\n", optarg);
440 return -1;
441 }
442 ok++;
443 break;
444
445 default:
446 memset(&fw, 0, sizeof (fw));
447 if (m) {
448 m->parse(c - m->option_offset, argv, 0,
449 &m->tflags, NULL, &m->t);
450 } else {
451 fprintf(stderr," failed to find target %s\n\n", optarg);
452 return -1;
453
454 }
455 ok++;
456 break;
457
458 }
459 }
460
461 if (iargc > optind) {
462 if (matches(argv[optind], "index") == 0) {
463 if (get_u32(&index, argv[optind + 1], 10)) {
464 fprintf(stderr, "Illegal \"index\"\n");
465 free_opts(opts);
466 return -1;
467 }
468 iok++;
469
470 optind += 2;
471 }
472 }
473
474 if (!ok && !iok) {
475 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
476 return -1;
477 }
478
479 /* check that we passed the correct parameters to the target */
480 if (m)
481 m->final_check(m->tflags);
482
483 {
484 struct tcmsg *t = NLMSG_DATA(n);
485 if (t->tcm_parent != TC_H_ROOT
486 && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
487 hook = NF_IP_PRE_ROUTING;
488 } else {
489 hook = NF_IP_POST_ROUTING;
490 }
491 }
492
493 tail = NLMSG_TAIL(n);
494 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
495 fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
496 fprintf(stdout, "\ttarget: ");
497
498 if (m)
499 m->print(NULL, m->t, 0);
500 fprintf(stdout, " index %d\n", index);
501
502 if (strlen(tname) > 16) {
503 size = 16;
504 k[15] = 0;
505 } else {
506 size = 1 + strlen(tname);
507 }
508 strncpy(k, tname, size);
509
510 addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
511 addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
512 addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
513 if (m)
514 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
515 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
516
517 argc -= optind;
518 argv += optind;
519 *argc_p = rargc - iargc;
520 *argv_p = argv;
521
522 optind = 0;
523 free_opts(opts);
524 /* Clear flags if target will be used again */
525 m->tflags=0;
526 m->used=0;
527 /* Free allocated memory */
528 if (m->t)
529 free(m->t);
530
531
532 return 0;
533
534 }
535
536 static int
print_ipt(struct action_util * au,FILE * f,struct rtattr * arg)537 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
538 {
539 struct rtattr *tb[TCA_IPT_MAX + 1];
540 struct ipt_entry_target *t = NULL;
541
542 if (arg == NULL)
543 return -1;
544
545 lib_dir = getenv("IPTABLES_LIB_DIR");
546 if (!lib_dir)
547 lib_dir = IPT_LIB_DIR;
548
549 parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
550
551 if (tb[TCA_IPT_TABLE] == NULL) {
552 fprintf(f, "[NULL ipt table name ] assuming mangle ");
553 } else {
554 fprintf(f, "tablename: %s ",
555 rta_getattr_str(tb[TCA_IPT_TABLE]));
556 }
557
558 if (tb[TCA_IPT_HOOK] == NULL) {
559 fprintf(f, "[NULL ipt hook name ]\n ");
560 return -1;
561 } else {
562 __u32 hook;
563 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
564 fprintf(f, " hook: %s \n", ipthooks[hook]);
565 }
566
567 if (tb[TCA_IPT_TARG] == NULL) {
568 fprintf(f, "\t[NULL ipt target parameters ] \n");
569 return -1;
570 } else {
571 struct iptables_target *m = NULL;
572 t = RTA_DATA(tb[TCA_IPT_TARG]);
573 m = get_target_name(t->u.user.name);
574 if (NULL != m) {
575 if (0 > build_st(m, t)) {
576 fprintf(stderr, " %s error \n", m->name);
577 return -1;
578 }
579
580 opts =
581 merge_options(opts, m->extra_opts,
582 &m->option_offset);
583 } else {
584 fprintf(stderr, " failed to find target %s\n\n",
585 t->u.user.name);
586 return -1;
587 }
588 fprintf(f, "\ttarget ");
589 m->print(NULL, m->t, 0);
590 if (tb[TCA_IPT_INDEX] == NULL) {
591 fprintf(f, " [NULL ipt target index ]\n");
592 } else {
593 __u32 index;
594 index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
595 fprintf(f, " \n\tindex %d", index);
596 }
597
598 if (tb[TCA_IPT_CNT]) {
599 struct tc_cnt *c = RTA_DATA(tb[TCA_IPT_CNT]);;
600 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
601 }
602 if (show_stats) {
603 if (tb[TCA_IPT_TM]) {
604 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
605 print_tm(f,tm);
606 }
607 }
608 fprintf(f, " \n");
609
610 }
611 free_opts(opts);
612
613 return 0;
614 }
615
616 struct action_util ipt_action_util = {
617 .id = "ipt",
618 .parse_aopt = parse_ipt,
619 .print_aopt = print_ipt,
620 };
621