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 <iptables.h>
  18 #include <linux/netfilter_ipv4/ip_tables.h>
  19 #include "utils.h"
  20 #include "tc_util.h"
  21 #include <linux/tc_act/tc_ipt.h>
  22 #include <stdio.h>
  23 #include <dlfcn.h>
  24 #include <getopt.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <netdb.h>
  28 #include <stdlib.h>
  29 #include <ctype.h>
  30 #include <stdarg.h>
  31 #include <limits.h>
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34 #include <sys/wait.h>
  35
  36 static const char *pname = "tc-ipt";
  37 static const char *tname = "mangle";
  38 static const char *pversion = "0.1";
  39
  40 static const char *ipthooks[] = {
  41         "NF_IP_PRE_ROUTING",
  42         "NF_IP_LOCAL_IN",
  43         "NF_IP_FORWARD",
  44         "NF_IP_LOCAL_OUT",
  45         "NF_IP_POST_ROUTING",
  46 };
  47
  48 static struct option original_opts[] = {
  49         {"jump", 1, 0, 'j'},
  50         {0, 0, 0, 0}
  51 };
  52
  53 static struct iptables_target *t_list = NULL;
  54 static struct option *opts = original_opts;
  55 static unsigned int global_option_offset = 0;
  56 #define OPTION_OFFSET 256
  57
  58 char *lib_dir;
  59
  60 void
  61 register_target(struct iptables_target *me)
  62 {
  63 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  64 */
  65         me->next = t_list;
  66         t_list = me;
  67
  68 }
  69
  70 void
  71 exit_tryhelp(int status)
  72 {
  73         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  74                 pname, pname);
  75         exit(status);
  76 }
  77
  78 void
  79 exit_error(enum exittype status, char *msg, ...)
  80 {
  81         va_list args;
  82
  83         va_start(args, msg);
  84         fprintf(stderr, "%s v%s: ", pname, pversion);
  85         vfprintf(stderr, msg, args);
  86         va_end(args);
  87         fprintf(stderr, "\n");
  88         if (status == PARAMETER_PROBLEM)
  89                 exit_tryhelp(status);
  90         if (status == VERSION_PROBLEM)
  91                 fprintf(stderr,
  92                         "Perhaps iptables or your kernel needs to be upgraded.\n");
  93         exit(status);
  94 }
  95
  96 /* stolen from iptables 1.2.11
  97 They should really have them as a library so i can link to them
  98 Email them next time i remember
  99 */
 100
 101 char *
 102 addr_to_dotted(const struct in_addr *addrp)
 103 {
 104         static char buf[20];
 105         const unsigned char *bytep;
 106
 107         bytep = (const unsigned char *) &(addrp->s_addr);
 108         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 109         return buf;
 110 }
 111
 112 int string_to_number_ll(const char *s, unsigned long long min,
 113                         unsigned long long max,
 114                  unsigned long long *ret)
 115 {
 116         unsigned long long number;
 117         char *end;
 118
 119         /* Handle hex, octal, etc. */
 120         errno = 0;
 121         number = strtoull(s, &end, 0);
 122         if (*end == '\0' && end != s) {
 123                 /* we parsed a number, let's see if we want this */
 124                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 125                         *ret = number;
 126                         return 0;
 127                 }
 128         }
 129         return -1;
 130 }
 131
 132 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 133                        unsigned long *ret)
 134 {
 135         int result;
 136         unsigned long long number;
 137
 138         result = string_to_number_ll(s, min, max, &number);
 139         *ret = (unsigned long)number;
 140
 141         return result;
 142 }
 143
 144 int string_to_number(const char *s, unsigned int min, unsigned int max,
 145                 unsigned int *ret)
 146 {
 147         int result;
 148         unsigned long number;
 149
 150         result = string_to_number_l(s, min, max, &number);
 151         *ret = (unsigned int)number;
 152
 153         return result;
 154 }
 155
 156 static void free_opts(struct option *opts)
 157 {
 158         if (opts != original_opts) {
 159                 free(opts);
 160                 opts = original_opts;
 161                 global_option_offset = 0;
 162         }
 163 }
 164
 165 static struct option *
 166 merge_options(struct option *oldopts, const struct option *newopts,
 167               unsigned int *option_offset)
 168 {
 169         struct option *merge;
 170         unsigned int num_old, num_new, i;
 171
 172         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 173         for (num_new = 0; newopts[num_new].name; num_new++) ;
 174
 175         *option_offset = global_option_offset + OPTION_OFFSET;
 176
 177         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 178         memcpy(merge, oldopts, num_old * sizeof (struct option));
 179         for (i = 0; i < num_new; i++) {
 180                 merge[num_old + i] = newopts[i];
 181                 merge[num_old + i].val += *option_offset;
 182         }
 183         memset(merge + num_old + num_new, 0, sizeof (struct option));
 184
 185         return merge;
 186 }
 187
 188 static void *
 189 fw_calloc(size_t count, size_t size)
 190 {
 191         void *p;
 192
 193         if ((p = (void *) calloc(count, size)) == NULL) {
 194                 perror("iptables: calloc failed");
 195                 exit(1);
 196         }
 197         return p;
 198 }
 199
 200 static struct iptables_target *
 201 find_t(char *name)
 202 {
 203         struct iptables_target *m;
 204         for (m = t_list; m; m = m->next) {
 205                 if (strcmp(m->name, name) == 0)
 206                         return m;
 207         }
 208
 209         return NULL;
 210 }
 211
 212 static struct iptables_target *
 213 get_target_name(const char *name)
 214 {
 215         void *handle;
 216         char *error;
 217         char *new_name, *lname;
 218         struct iptables_target *m;
 219         char path[strlen(lib_dir) + sizeof ("/libipt_.so") + strlen(name)];
 220
 221         new_name = malloc(strlen(name) + 1);
 222         lname = malloc(strlen(name) + 1);
 223         if (new_name)
 224                 memset(new_name, '\0', strlen(name) + 1);
 225         else
 226                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 227
 228         if (lname)
 229                 memset(lname, '\0', strlen(name) + 1);
 230         else
 231                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 232
 233         strcpy(new_name, name);
 234         strcpy(lname, name);
 235
 236         if (isupper(lname[0])) {
 237                 int i;
 238                 for (i = 0; i < strlen(name); i++) {
 239                         lname[i] = tolower(lname[i]);
 240                 }
 241         }
 242
 243         if (islower(new_name[0])) {
 244                 int i;
 245                 for (i = 0; i < strlen(new_name); i++) {
 246                         new_name[i] = toupper(new_name[i]);
 247                 }
 248         }
 249
 250         sprintf(path,  "%s/libipt_%s.so",lib_dir, new_name);
 251         handle = dlopen(path, RTLD_LAZY);
 252         if (!handle) {
 253                 sprintf(path, lib_dir, "/libipt_%s.so", lname);
 254                 handle = dlopen(path, RTLD_LAZY);
 255                 if (!handle) {
 256                         fputs(dlerror(), stderr);
 257                         printf("\n");
 258                         return NULL;
 259                 }
 260         }
 261
 262         m = dlsym(handle, new_name);
 263         if ((error = dlerror()) != NULL) {
 264                 m = (struct iptables_target *) dlsym(handle, lname);
 265                 if ((error = dlerror()) != NULL) {
 266                         m = find_t(new_name);
 267                         if (NULL == m) {
 268                                 m = find_t(lname);
 269                                 if (NULL == m) {
 270                                         fputs(error, stderr);
 271                                         fprintf(stderr, "\n");
 272                                         dlclose(handle);
 273                                         return NULL;
 274                                 }
 275                         }
 276                 }
 277         }
 278
 279         return m;
 280 }
 281
 282
 283 struct in_addr *dotted_to_addr(const char *dotted)
 284 {
 285         static struct in_addr addr;
 286         unsigned char *addrp;
 287         char *p, *q;
 288         unsigned int onebyte;
 289         int i;
 290         char buf[20];
 291
 292         /* copy dotted string, because we need to modify it */
 293         strncpy(buf, dotted, sizeof (buf) - 1);
 294         addrp = (unsigned char *) &(addr.s_addr);
 295
 296         p = buf;
 297         for (i = 0; i < 3; i++) {
 298                 if ((q = strchr(p, '.')) == NULL)
 299                         return (struct in_addr *) NULL;
 300
 301                 *q = '\0';
 302                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 303                         return (struct in_addr *) NULL;
 304
 305                 addrp[i] = (unsigned char) onebyte;
 306                 p = q + 1;
 307         }
 308
 309         /* we've checked 3 bytes, now we check the last one */
 310         if (string_to_number(p, 0, 255, &onebyte) == -1)
 311                 return (struct in_addr *) NULL;
 312
 313         addrp[3] = (unsigned char) onebyte;
 314
 315         return &addr;
 316 }
 317
 318 static void set_revision(char *name, u_int8_t revision)
 319 {
 320         /* Old kernel sources don't have ".revision" field,
 321         *  but we stole a byte from name. */
 322         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 323         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 324 }
 325
 326 /*
 327  * we may need to check for version mismatch
 328 */
 329 int
 330 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 331 {
 332         unsigned int nfcache = 0;
 333
 334         if (target) {
 335                 size_t size;
 336
 337                 size =
 338                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 339
 340                 if (NULL == t) {
 341                         target->t = fw_calloc(1, size);
 342                         target->t->u.target_size = size;
 343
 344                         if (target->init != NULL)
 345                                 target->init(target->t, &nfcache);
 346                         set_revision(target->t->u.user.name, target->revision);
 347                 } else {
 348                         target->t = t;
 349                 }
 350                 strcpy(target->t->u.user.name, target->name);
 351                 return 0;
 352         }
 353
 354         return -1;
 355 }
 356
 357 static int parse_ipt(struct action_util *a,int *argc_p,
 358                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 359 {
 360         struct iptables_target *m = NULL;
 361         struct ipt_entry fw;
 362         struct rtattr *tail;
 363         int c;
 364         int rargc = *argc_p;
 365         char **argv = *argv_p;
 366         int argc = 0, iargc = 0;
 367         char k[16];
 368         int res = -1;
 369         int size = 0;
 370         int iok = 0, ok = 0;
 371         __u32 hook = 0, index = 0;
 372         res = 0;
 373
 374         lib_dir = getenv("IPTABLES_LIB_DIR");
 375         if (!lib_dir)
 376                 lib_dir = IPT_LIB_DIR;
 377
 378         {
 379                 int i;
 380                 for (i = 0; i < rargc; i++) {
 381                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 382                                 break;
 383                         }
 384                 }
 385                 iargc = argc = i;
 386         }
 387
 388         if (argc <= 2) {
 389                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 390                 return -1;
 391         }
 392
 393         while (1) {
 394                 c = getopt_long(argc, argv, "j:", opts, NULL);
 395                 if (c == -1)
 396                         break;
 397                 switch (c) {
 398                 case 'j':
 399                         m = get_target_name(optarg);
 400                         if (NULL != m) {
 401
 402                                 if (0 > build_st(m, NULL)) {
 403                                         printf(" %s error \n", m->name);
 404                                         return -1;
 405                                 }
 406                                 opts =
 407                                     merge_options(opts, m->extra_opts,
 408                                                   &m->option_offset);
 409                         } else {
 410                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 411                                 return -1;
 412                         }
 413                         ok++;
 414                         break;
 415
 416                 default:
 417                         memset(&fw, 0, sizeof (fw));
 418                         if (m) {
 419                                 m->parse(c - m->option_offset, argv, 0,
 420                                          &m->tflags, NULL, &m->t);
 421                         } else {
 422                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 423                                 return -1;
 424
 425                         }
 426                         ok++;
 427                         break;
 428
 429                 }
 430         }
 431
 432         if (iargc > optind) {
 433                 if (matches(argv[optind], "index") == 0) {
 434                         if (get_u32(&index, argv[optind + 1], 10)) {
 435                                 fprintf(stderr, "Illegal \"index\"\n");
 436                                 free_opts(opts);
 437                                 return -1;
 438                         }
 439                         iok++;
 440
 441                         optind += 2;
 442                 }
 443         }
 444
 445         if (!ok && !iok) {
 446                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 447                 return -1;
 448         }
 449
 450         /* check that we passed the correct parameters to the target */
 451         if (m)
 452                 m->final_check(m->tflags);
 453
 454         {
 455                 struct tcmsg *t = NLMSG_DATA(n);
 456                 if (t->tcm_parent != TC_H_ROOT
 457                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 458                         hook = NF_IP_PRE_ROUTING;
 459                 } else {
 460                         hook = NF_IP_POST_ROUTING;
 461                 }
 462         }
 463
 464         tail = NLMSG_TAIL(n);
 465         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 466         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 467         fprintf(stdout, "\ttarget: ");
 468
 469         if (m)
 470                 m->print(NULL, m->t, 0);
 471         fprintf(stdout, " index %d\n", index);
 472
 473         if (strlen(tname) > 16) {
 474                 size = 16;
 475                 k[15] = 0;
 476         } else {
 477                 size = 1 + strlen(tname);
 478         }
 479         strncpy(k, tname, size);
 480
 481         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 482         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 483         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 484         if (m)
 485                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 486         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 487
 488         argc -= optind;
 489         argv += optind;
 490         *argc_p = rargc - iargc;
 491         *argv_p = argv;
 492
 493         optind = 1;
 494         free_opts(opts);
 495
 496         return 0;
 497
 498 }
 499
 500 static int
 501 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 502 {
 503         struct rtattr *tb[TCA_IPT_MAX + 1];
 504         struct ipt_entry_target *t = NULL;
 505
 506         if (arg == NULL)
 507                 return -1;
 508
 509         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 510
 511         if (tb[TCA_IPT_TABLE] == NULL) {
 512                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 513         } else {
 514                 fprintf(f, "tablename: %s ",
 515                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 516         }
 517
 518         if (tb[TCA_IPT_HOOK] == NULL) {
 519                 fprintf(f, "[NULL ipt hook name ]\n ");
 520                 return -1;
 521         } else {
 522                 __u32 hook;
 523                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 524                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 525         }
 526
 527         if (tb[TCA_IPT_TARG] == NULL) {
 528                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 529                 return -1;
 530         } else {
 531                 struct iptables_target *m = NULL;
 532                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 533                 m = get_target_name(t->u.user.name);
 534                 if (NULL != m) {
 535                         if (0 > build_st(m, t)) {
 536                                 fprintf(stderr, " %s error \n", m->name);
 537                                 return -1;
 538                         }
 539
 540                         opts =
 541                             merge_options(opts, m->extra_opts,
 542                                           &m->option_offset);
 543                 } else {
 544                         fprintf(stderr, " failed to find target %s\n\n",
 545                                 t->u.user.name);
 546                         return -1;
 547                 }
 548                 fprintf(f, "\ttarget ");
 549                 m->print(NULL, m->t, 0);
 550                 if (tb[TCA_IPT_INDEX] == NULL) {
 551                         fprintf(f, " [NULL ipt target index ]\n");
 552                 } else {
 553                         __u32 index;
 554                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 555                         fprintf(f, " \n\tindex %d", index);
 556                 }
 557
 558                 if (tb[TCA_IPT_CNT]) {
 559                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 560                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 561                 }
 562                 if (show_stats) {
 563                         if (tb[TCA_IPT_TM]) {
 564                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 565                                 print_tm(f,tm);
 566                         }
 567                 }
 568                 fprintf(f, " \n");
 569
 570         }
 571         free_opts(opts);
 572
 573         return 0;
 574 }
 575
 576 struct action_util ipt_action_util = {
 577         .id = "ipt",
 578         .parse_aopt = parse_ipt,
 579         .print_aopt = print_ipt,
 580 };
 581