tc/m_ipt.c

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