1 /*
2 * m_xt.c xtables 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 <net/if.h>
18 #include <limits.h>
19 #include <linux/netfilter.h>
20 #include <linux/netfilter_ipv4/ip_tables.h>
21 #include <xtables.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 <unistd.h>
35 #include <fcntl.h>
36 #include <sys/wait.h>
37 #ifndef XT_LIB_DIR
38 # define XT_LIB_DIR "/lib/xtables"
39 #endif
40
41 #ifndef __ALIGN_KERNEL
42 #define __ALIGN_KERNEL(x, a) \
43 __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
44 #define __ALIGN_KERNEL_MASK(x, mask) \
45 (((x) + (mask)) & ~(mask))
46 #endif
47
48 #ifndef ALIGN
49 #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
50 #endif
51
52 static const char *tname = "mangle";
53
54 char *lib_dir;
55
56 static const char * const ipthooks[] = {
57 "NF_IP_PRE_ROUTING",
58 "NF_IP_LOCAL_IN",
59 "NF_IP_FORWARD",
60 "NF_IP_LOCAL_OUT",
61 "NF_IP_POST_ROUTING",
62 };
63
64 static struct option original_opts[] = {
65 {
66 .name = "jump",
67 .has_arg = 1,
68 .val = 'j'
69 },
70 {0, 0, 0, 0}
71 };
72
73 static struct xtables_globals tcipt_globals = {
74 .option_offset = 0,
75 .program_name = "tc-ipt",
76 .program_version = "0.2",
77 .orig_opts = original_opts,
78 .opts = original_opts,
79 .exit_err = NULL,
80 #if XTABLES_VERSION_CODE >= 11
81 .compat_rev = xtables_compatible_revision,
82 #endif
83 };
84
85 /*
86 * we may need to check for version mismatch
87 */
88 static int
build_st(struct xtables_target * target,struct xt_entry_target * t)89 build_st(struct xtables_target *target, struct xt_entry_target *t)
90 {
91
92 size_t size =
93 XT_ALIGN(sizeof(struct xt_entry_target)) + target->size;
94
95 if (t == NULL) {
96 target->t = xtables_calloc(1, size);
97 target->t->u.target_size = size;
98 strncpy(target->t->u.user.name, target->name,
99 sizeof(target->t->u.user.name) - 1);
100 target->t->u.user.revision = target->revision;
101
102 if (target->init != NULL)
103 target->init(target->t);
104 } else {
105 target->t = t;
106 }
107 return 0;
108
109 }
110
set_lib_dir(void)111 static void set_lib_dir(void)
112 {
113
114 lib_dir = getenv("XTABLES_LIBDIR");
115 if (!lib_dir) {
116 lib_dir = getenv("IPTABLES_LIB_DIR");
117 if (lib_dir)
118 fprintf(stderr, "using deprecated IPTABLES_LIB_DIR\n");
119 }
120 if (lib_dir == NULL)
121 lib_dir = XT_LIB_DIR;
122
123 }
124
get_xtables_target_opts(struct xtables_globals * globals,struct xtables_target * m)125 static int get_xtables_target_opts(struct xtables_globals *globals,
126 struct xtables_target *m)
127 {
128 struct option *opts;
129
130 #if XTABLES_VERSION_CODE >= 6
131 opts = xtables_options_xfrm(globals->orig_opts,
132 globals->opts,
133 m->x6_options,
134 &m->option_offset);
135 #else
136 opts = xtables_merge_options(globals->opts,
137 m->extra_opts,
138 &m->option_offset);
139 #endif
140 if (!opts)
141 return -1;
142 globals->opts = opts;
143 return 0;
144 }
145
parse_ipt(struct action_util * a,int * argc_p,char *** argv_p,int tca_id,struct nlmsghdr * n)146 static int parse_ipt(struct action_util *a, int *argc_p,
147 char ***argv_p, int tca_id, struct nlmsghdr *n)
148 {
149 struct xtables_target *m = NULL;
150 #if XTABLES_VERSION_CODE >= 6
151 struct ipt_entry fw = {};
152 #endif
153 struct rtattr *tail;
154
155 int c;
156 char **argv = *argv_p;
157 int argc;
158 char k[16];
159 int size = 0;
160 int iok = 0, ok = 0;
161 __u32 hook = 0, index = 0;
162
163 /* copy tcipt_globals because .opts will be modified by iptables */
164 struct xtables_globals tmp_tcipt_globals = tcipt_globals;
165
166 xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
167 set_lib_dir();
168
169 /* parse only up until the next action */
170 for (argc = 0; argc < *argc_p; argc++) {
171 if (!argv[argc] || !strcmp(argv[argc], "action"))
172 break;
173 }
174
175 if (argc <= 2) {
176 fprintf(stderr,
177 "too few arguments for xt, need at least '-j <target>'\n");
178 return -1;
179 }
180
181 while (1) {
182 c = getopt_long(argc, argv, "j:", tmp_tcipt_globals.opts, NULL);
183 if (c == -1)
184 break;
185 switch (c) {
186 case 'j':
187 m = xtables_find_target(optarg, XTF_TRY_LOAD);
188 if (!m) {
189 fprintf(stderr,
190 " failed to find target %s\n\n",
191 optarg);
192 return -1;
193 }
194
195 if (build_st(m, NULL) < 0) {
196 printf(" %s error\n", m->name);
197 return -1;
198 }
199
200 if (get_xtables_target_opts(&tmp_tcipt_globals,
201 m) < 0) {
202 fprintf(stderr,
203 " failed to find additional options for target %s\n\n",
204 optarg);
205 return -1;
206 }
207 ok++;
208 break;
209
210 default:
211 #if XTABLES_VERSION_CODE >= 6
212 if (m != NULL && m->x6_parse != NULL) {
213 xtables_option_tpcall(c, argv, 0, m, &fw);
214 #else
215 if (m != NULL && m->parse != NULL) {
216 m->parse(c - m->option_offset, argv, 0,
217 &m->tflags, NULL, &m->t);
218 #endif
219 } else {
220 fprintf(stderr,
221 "failed to find target %s\n\n", optarg);
222 return -1;
223
224 }
225 ok++;
226 break;
227 }
228 }
229
230 if (argc > optind) {
231 if (matches(argv[optind], "index") == 0) {
232 if (get_u32(&index, argv[optind + 1], 10)) {
233 fprintf(stderr, "Illegal \"index\"\n");
234 xtables_free_opts(1);
235 return -1;
236 }
237 iok++;
238
239 optind += 2;
240 }
241 }
242
243 if (!ok && !iok) {
244 fprintf(stderr, " ipt Parser BAD!! (%s)\n", *argv);
245 return -1;
246 }
247
248 /* check that we passed the correct parameters to the target */
249 #if XTABLES_VERSION_CODE >= 6
250 if (m)
251 xtables_option_tfcall(m);
252 #else
253 if (m && m->final_check)
254 m->final_check(m->tflags);
255 #endif
256
257 {
258 struct tcmsg *t = NLMSG_DATA(n);
259
260 if (t->tcm_parent != TC_H_ROOT
261 && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
262 hook = NF_IP_PRE_ROUTING;
263 } else {
264 hook = NF_IP_POST_ROUTING;
265 }
266 }
267
268 tail = NLMSG_TAIL(n);
269 addattr_l(n, MAX_MSG, tca_id, NULL, 0);
270 fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
271 fprintf(stdout, "\ttarget: ");
272
273 if (m) {
274 if (m->print)
275 m->print(NULL, m->t, 0);
276 else
277 printf("%s ", m->name);
278 }
279 fprintf(stdout, " index %d\n", index);
280
281 if (strlen(tname) >= 16) {
282 size = 15;
283 k[15] = 0;
284 } else {
285 size = 1 + strlen(tname);
286 }
287 strncpy(k, tname, size);
288
289 addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
290 addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
291 addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
292 if (m)
293 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
294 tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
295
296 argv += optind;
297 *argc_p -= argc;
298 *argv_p = argv;
299
300 optind = 0;
301 xtables_free_opts(1);
302
303 if (m) {
304 /* Clear flags if target will be used again */
305 m->tflags = 0;
306 m->used = 0;
307 /* Free allocated memory */
308 if (m->t)
309 free(m->t);
310 }
311
312 return 0;
313
314 }
315
316 static int
317 print_ipt(struct action_util *au, FILE *f, struct rtattr *arg)
318 {
319 struct xtables_target *m;
320 struct rtattr *tb[TCA_IPT_MAX + 1];
321 struct xt_entry_target *t = NULL;
322
323 if (arg == NULL)
324 return -1;
325
326 /* copy tcipt_globals because .opts will be modified by iptables */
327 struct xtables_globals tmp_tcipt_globals = tcipt_globals;
328
329 xtables_init_all(&tmp_tcipt_globals, NFPROTO_IPV4);
330 set_lib_dir();
331
332 parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
333
334 if (tb[TCA_IPT_TABLE] == NULL) {
335 fprintf(f, "[NULL ipt table name ] assuming mangle ");
336 } else {
337 fprintf(f, "tablename: %s ",
338 rta_getattr_str(tb[TCA_IPT_TABLE]));
339 }
340
341 if (tb[TCA_IPT_HOOK] == NULL) {
342 fprintf(f, "[NULL ipt hook name ]\n ");
343 return -1;
344 } else {
345 __u32 hook;
346
347 hook = rta_getattr_u32(tb[TCA_IPT_HOOK]);
348 fprintf(f, " hook: %s\n", ipthooks[hook]);
349 }
350
351 if (tb[TCA_IPT_TARG] == NULL) {
352 fprintf(f, "\t[NULL ipt target parameters ]\n");
353 return -1;
354 }
355
356 t = RTA_DATA(tb[TCA_IPT_TARG]);
357 m = xtables_find_target(t->u.user.name, XTF_TRY_LOAD);
358 if (!m) {
359 fprintf(stderr, " failed to find target %s\n\n",
360 t->u.user.name);
361 return -1;
362 }
363 if (build_st(m, t) < 0) {
364 fprintf(stderr, " %s error\n", m->name);
365 return -1;
366 }
367
368 if (get_xtables_target_opts(&tmp_tcipt_globals, m) < 0) {
369 fprintf(stderr,
370 " failed to find additional options for target %s\n\n",
371 t->u.user.name);
372 return -1;
373 }
374 fprintf(f, "\ttarget ");
375 m->print(NULL, m->t, 0);
376 if (tb[TCA_IPT_INDEX] == NULL) {
377 fprintf(f, " [NULL ipt target index ]\n");
378 } else {
379 __u32 index;
380
381 index = rta_getattr_u32(tb[TCA_IPT_INDEX]);
382 fprintf(f, "\n\tindex %u", index);
383 }
384
385 if (tb[TCA_IPT_CNT]) {
386 struct tc_cnt *c = RTA_DATA(tb[TCA_IPT_CNT]);
387
388 fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
389 }
390 if (show_stats) {
391 if (tb[TCA_IPT_TM]) {
392 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
393
394 print_tm(f, tm);
395 }
396 }
397 fprintf(f, "\n");
398
399 xtables_free_opts(1);
400
401 return 0;
402 }
403
404 struct action_util xt_action_util = {
405 .id = "xt",
406 .parse_aopt = parse_ipt,
407 .print_aopt = print_ipt,
408 };
409