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  * TODO: bad bad hardcoding IPT_LIB_DIR and PROC_SYS_MODPROBE
  13  *
  14 */
  15
  16 #include <syslog.h>
  17 #include <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20 #include <iptables.h>
  21 #include <linux/netfilter_ipv4/ip_tables.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 <limits.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37 #include <sys/wait.h>
  38
  39 const char *pname = "tc-ipt";
  40 const char *tname = "mangle";
  41 const char *pversion = "0.1";
  42
  43 #ifndef TRUE
  44 #define TRUE 1
  45 #endif
  46 #ifndef FALSE
  47 #define FALSE 0
  48 #endif
  49
  50 #ifndef IPT_LIB_DIR
  51 #define IPT_LIB_DIR "/usr/local/lib/iptables"
  52 #endif
  53
  54 #ifndef PROC_SYS_MODPROBE
  55 #define PROC_SYS_MODPROBE "/proc/sys/kernel/modprobe"
  56 #endif
  57
  58 static const char *ipthooks[] = {
  59         "NF_IP_PRE_ROUTING",
  60         "NF_IP_LOCAL_IN",
  61         "NF_IP_FORWARD",
  62         "NF_IP_LOCAL_OUT",
  63         "NF_IP_POST_ROUTING",
  64 };
  65
  66 static struct option original_opts[] = {
  67         {"jump", 1, 0, 'j'},
  68         {0, 0, 0, 0}
  69 };
  70
  71 static struct iptables_target *t_list = NULL;
  72 static unsigned int global_option_offset = 0;
  73 #define OPTION_OFFSET 256
  74
  75 #if 0
  76 /* no clue why register match is within targets
  77  figure out later. Talk to Harald -- JHS
  78 */
  79 void
  80 register_match(struct iptables_match *me)
  81 {
  82 /*      fprintf(stderr, "\nDummy register_match\n"); */
  83 }
  84
  85 void
  86 register_target(struct iptables_target *me)
  87 {
  88 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  89 */
  90         me->next = t_list;
  91         t_list = me;
  92
  93 }
  94 #endif
  95
  96 void
  97 exit_tryhelp(int status)
  98 {
  99         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
 100                 pname, pname);
 101         exit(status);
 102 }
 103
 104 void
 105 exit_error(enum exittype status, char *msg, ...)
 106 {
 107         va_list args;
 108
 109         va_start(args, msg);
 110         fprintf(stderr, "%s v%s: ", pname, pversion);
 111         vfprintf(stderr, msg, args);
 112         va_end(args);
 113         fprintf(stderr, "\n");
 114         if (status == PARAMETER_PROBLEM)
 115                 exit_tryhelp(status);
 116         if (status == VERSION_PROBLEM)
 117                 fprintf(stderr,
 118                         "Perhaps iptables or your kernel needs to be upgraded.\n");
 119         exit(status);
 120 }
 121
 122 /* stolen from iptables 1.2.11
 123 They should really have them as a library so i can link to them
 124 Email them next time i remember
 125 */
 126
 127 char *
 128 addr_to_dotted(const struct in_addr *addrp)
 129 {
 130         static char buf[20];
 131         const unsigned char *bytep;
 132
 133         bytep = (const unsigned char *) &(addrp->s_addr);
 134         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 135         return buf;
 136 }
 137
 138 int string_to_number_ll(const char *s, unsigned long long min,
 139                         unsigned long long max,
 140                  unsigned long long *ret)
 141 {
 142         unsigned long long number;
 143         char *end;
 144
 145         /* Handle hex, octal, etc. */
 146         errno = 0;
 147         number = strtoull(s, &end, 0);
 148         if (*end == '\0' && end != s) {
 149                 /* we parsed a number, let's see if we want this */
 150                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 151                         *ret = number;
 152                         return 0;
 153                 }
 154         }
 155         return -1;
 156 }
 157
 158 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 159                        unsigned long *ret)
 160 {
 161         int result;
 162         unsigned long long number;
 163
 164         result = string_to_number_ll(s, min, max, &number);
 165         *ret = (unsigned long)number;
 166
 167         return result;
 168 }
 169
 170 int string_to_number(const char *s, unsigned int min, unsigned int max,
 171                 unsigned int *ret)
 172 {
 173         int result;
 174         unsigned long number;
 175
 176         result = string_to_number_l(s, min, max, &number);
 177         *ret = (unsigned int)number;
 178
 179         return result;
 180 }
 181
 182 #if 0
 183 static int
 184 string_to_number(const char *s, unsigned int min, unsigned int max,
 185                  unsigned int *ret)
 186 {
 187         long number;
 188         char *end;
 189
 190         /* Handle hex, octal, etc. */
 191         errno = 0;
 192         number = strtol(s, &end, 0);
 193         if (*end == '\0' && end != s) {
 194                 /* we parsed a number, let's see if we want this */
 195                 if (errno != ERANGE && min <= number && number <= max) {
 196                         *ret = number;
 197                         return 0;
 198                 }
 199         }
 200         return -1;
 201 }
 202 #endif
 203
 204 static struct option *
 205 copy_options(struct option *oldopts)
 206 {
 207         struct option *merge;
 208         unsigned int num_old;
 209         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 210         merge = malloc(sizeof (struct option) * (num_old + 1));
 211         if (NULL == merge)
 212                 return NULL;
 213         memcpy(merge, oldopts, num_old * sizeof (struct option));
 214         memset(merge + num_old, 0, sizeof (struct option));
 215         return merge;
 216 }
 217
 218 static struct option *
 219 merge_options(struct option *oldopts, const struct option *newopts,
 220               unsigned int *option_offset)
 221 {
 222         struct option *merge;
 223         unsigned int num_old, num_new, i;
 224
 225         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 226         for (num_new = 0; newopts[num_new].name; num_new++) ;
 227
 228         *option_offset = global_option_offset + OPTION_OFFSET;
 229
 230         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 231         memcpy(merge, oldopts, num_old * sizeof (struct option));
 232         for (i = 0; i < num_new; i++) {
 233                 merge[num_old + i] = newopts[i];
 234                 merge[num_old + i].val += *option_offset;
 235         }
 236         memset(merge + num_old + num_new, 0, sizeof (struct option));
 237
 238         return merge;
 239 }
 240
 241 static void *
 242 fw_calloc(size_t count, size_t size)
 243 {
 244         void *p;
 245
 246         if ((p = (void *) calloc(count, size)) == NULL) {
 247                 perror("iptables: calloc failed");
 248                 exit(1);
 249         }
 250         return p;
 251 }
 252
 253 #if 0
 254 static void *
 255 fw_malloc(size_t size)
 256 {
 257         void *p;
 258
 259         if ((p = (void *) malloc(size)) == NULL) {
 260                 perror("iptables: malloc failed");
 261                 exit(1);
 262         }
 263         return p;
 264 }
 265
 266 static int
 267 check_inverse(const char option[], int *invert)
 268 {
 269         if (option && strcmp(option, "!") == 0) {
 270                 if (*invert)
 271                         exit_error(PARAMETER_PROBLEM,
 272                                    "Multiple `!' flags not allowed");
 273
 274                 *invert = TRUE;
 275                 return TRUE;
 276         }
 277         return FALSE;
 278 }
 279 #endif
 280
 281 static struct iptables_target *
 282 find_t(char *name)
 283 {
 284         struct iptables_target *m;
 285         for (m = t_list; m; m = m->next) {
 286                 if (strcmp(m->name, name) == 0)
 287                         return m;
 288         }
 289
 290         return NULL;
 291 }
 292
 293 static struct iptables_target *
 294 get_target_name(char *name)
 295 {
 296         void *handle;
 297         char *error;
 298         char *new_name, *lname;
 299         struct iptables_target *m;
 300
 301         char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
 302
 303         new_name = malloc(strlen(name) + 1);
 304         lname = malloc(strlen(name) + 1);
 305         if (new_name)
 306                 memset(new_name, '\0', strlen(name) + 1);
 307         else
 308                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 309
 310         if (lname)
 311                 memset(lname, '\0', strlen(name) + 1);
 312         else
 313                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 314
 315         strcpy(new_name, name);
 316         strcpy(lname, name);
 317
 318         if (isupper(lname[0])) {
 319                 int i;
 320                 for (i = 0; i < strlen(name); i++) {
 321                         lname[i] = tolower(lname[i]);
 322                 }
 323         }
 324
 325         if (islower(new_name[0])) {
 326                 int i;
 327                 for (i = 0; i < strlen(new_name); i++) {
 328                         new_name[i] = toupper(new_name[i]);
 329                 }
 330         }
 331
 332         sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
 333         handle = dlopen(path, RTLD_LAZY);
 334         if (!handle) {
 335                 sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
 336                 handle = dlopen(path, RTLD_LAZY);
 337                 if (!handle) {
 338                         fputs(dlerror(), stderr);
 339                         printf("\n");
 340                         return NULL;
 341                 }
 342         }
 343
 344         m = dlsym(handle, new_name);
 345         if ((error = dlerror()) != NULL) {
 346                 m = (struct iptables_target *) dlsym(handle, lname);
 347                 if ((error = dlerror()) != NULL) {
 348                         m = find_t(new_name);
 349                         if (NULL == m) {
 350                                 m = find_t(lname);
 351                                 if (NULL == m) {
 352                                         fputs(error, stderr);
 353                                         fprintf(stderr, "\n");
 354                                         dlclose(handle);
 355                                         return NULL;
 356                                 }
 357                         }
 358                 }
 359         }
 360
 361         return m;
 362 }
 363
 364 #if 0
 365 static char *
 366 addr_to_dotted(const struct in_addr *addrp)
 367 {
 368         static char buf[20];
 369         const unsigned char *bytep;
 370
 371         bytep = (const unsigned char *) &(addrp->s_addr);
 372         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 373         return buf;
 374 }
 375 #endif
 376
 377 struct in_addr *dotted_to_addr(const char *dotted)
 378 {
 379         static struct in_addr addr;
 380         unsigned char *addrp;
 381         char *p, *q;
 382         unsigned int onebyte;
 383         int i;
 384         char buf[20];
 385
 386         /* copy dotted string, because we need to modify it */
 387         strncpy(buf, dotted, sizeof (buf) - 1);
 388         addrp = (unsigned char *) &(addr.s_addr);
 389
 390         p = buf;
 391         for (i = 0; i < 3; i++) {
 392                 if ((q = strchr(p, '.')) == NULL)
 393                         return (struct in_addr *) NULL;
 394
 395                 *q = '\0';
 396                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 397                         return (struct in_addr *) NULL;
 398
 399                 addrp[i] = (unsigned char) onebyte;
 400                 p = q + 1;
 401         }
 402
 403         /* we've checked 3 bytes, now we check the last one */
 404         if (string_to_number(p, 0, 255, &onebyte) == -1)
 405                 return (struct in_addr *) NULL;
 406
 407         addrp[3] = (unsigned char) onebyte;
 408
 409         return &addr;
 410 }
 411
 412 int
 413 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 414 {
 415         unsigned int nfcache = 0;
 416
 417         if (target) {
 418                 size_t size;
 419
 420                 size =
 421                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 422
 423                 if (NULL == t) {
 424                         target->t = fw_calloc(1, size);
 425                         target->init(target->t, &nfcache);
 426                         target->t->u.target_size = size;
 427                 } else {
 428                         target->t = t;
 429                 }
 430                 strcpy(target->t->u.user.name, target->name);
 431                 return 0;
 432         }
 433
 434         return -1;
 435 }
 436
 437 static int parse_ipt(struct action_util *a,int *argc_p,
 438                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 439 {
 440         struct iptables_target *m = NULL;
 441         struct ipt_entry fw;
 442         struct rtattr *tail;
 443         int c;
 444         int rargc = *argc_p;
 445         char **argv = *argv_p;
 446         struct option *opts;
 447         int argc = 0, iargc = 0;
 448         char k[16];
 449         int res = -1;
 450         int size = 0;
 451         int iok = 0, ok = 0;
 452         __u32 hook = 0, index = 0;
 453         res = 0;
 454
 455         {
 456                 int i;
 457                 for (i = 0; i < rargc; i++) {
 458                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 459                                 break;
 460                         }
 461                 }
 462                 iargc = argc = i;
 463         }
 464
 465         if (argc <= 2) {
 466                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 467                 return -1;
 468         }
 469
 470         opts = copy_options(original_opts);
 471
 472         if (NULL == opts)
 473                 return -1;
 474
 475         while (1) {
 476                 c = getopt_long(argc, argv, "j:", opts, NULL);
 477                 if (c == -1)
 478                         break;
 479                 switch (c) {
 480                 case 'j':
 481                         m = get_target_name(optarg);
 482                         if (NULL != m) {
 483
 484                                 if (0 > build_st(m, NULL)) {
 485                                         printf(" %s error \n", m->name);
 486                                         return -1;
 487                                 }
 488                                 opts =
 489                                     merge_options(opts, m->extra_opts,
 490                                                   &m->option_offset);
 491                         } else {
 492                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 493                                 return -1;
 494                         }
 495                         ok++;
 496                         break;
 497
 498                 default:
 499                         memset(&fw, 0, sizeof (fw));
 500                         if (m) {
 501                                 unsigned int fake_flags = 0;
 502                                 m->parse(c - m->option_offset, argv, 0,
 503                                          &fake_flags, NULL, &m->t);
 504                         } else {
 505                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 506                                 return -1;
 507
 508                         }
 509                         ok++;
 510
 511                         /*m->final_check(m->t); -- Is this necessary?
 512                         ** useful when theres depencies
 513                         ** eg ipt_TCPMSS.c has have the TCP match loaded
 514                         ** before this can be used;
 515                         **  also seems the ECN target needs it
 516                         */
 517
 518                         break;
 519
 520                 }
 521         }
 522
 523         if (iargc > optind) {
 524                 if (matches(argv[optind], "index") == 0) {
 525                         if (get_u32(&index, argv[optind + 1], 10)) {
 526                                 fprintf(stderr, "Illegal \"index\"\n");
 527                                 return -1;
 528                         }
 529                         iok++;
 530
 531                         optind += 2;
 532                 }
 533         }
 534
 535         if (!ok && !iok) {
 536                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 537                 return -1;
 538         }
 539
 540         {
 541                 struct tcmsg *t = NLMSG_DATA(n);
 542                 if (t->tcm_parent != TC_H_ROOT
 543                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 544                         hook = NF_IP_PRE_ROUTING;
 545                 } else {
 546                         hook = NF_IP_POST_ROUTING;
 547                 }
 548         }
 549
 550         tail = NLMSG_TAIL(n);
 551         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 552         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 553         fprintf(stdout, "\ttarget: ");
 554
 555         if (m)
 556                 m->print(NULL, m->t, 0);
 557         fprintf(stdout, " index %d\n", index);
 558
 559         if (strlen(tname) > 16) {
 560                 size = 16;
 561                 k[15] = 0;
 562         } else {
 563                 size = 1 + strlen(tname);
 564         }
 565         strncpy(k, tname, size);
 566
 567         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 568         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 569         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 570         if (m)
 571                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 572         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 573
 574         argc -= optind;
 575         argv += optind;
 576         *argc_p = rargc - iargc;
 577         *argv_p = argv;
 578
 579         optind = 1;
 580
 581         return 0;
 582
 583 }
 584
 585 static int
 586 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 587 {
 588         struct rtattr *tb[TCA_IPT_MAX + 1];
 589         struct ipt_entry_target *t = NULL;
 590         struct option *opts;
 591
 592         if (arg == NULL)
 593                 return -1;
 594
 595         opts = copy_options(original_opts);
 596
 597         if (NULL == opts)
 598                 return -1;
 599         memset(tb, 0, sizeof (tb));
 600         parse_rtattr(tb, TCA_IPT_MAX, RTA_DATA(arg), RTA_PAYLOAD(arg));
 601
 602         if (tb[TCA_IPT_TABLE] == NULL) {
 603                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 604         } else {
 605                 fprintf(f, "tablename: %s ",
 606                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 607         }
 608
 609         if (tb[TCA_IPT_HOOK] == NULL) {
 610                 fprintf(f, "[NULL ipt hook name ]\n ");
 611                 return -1;
 612         } else {
 613                 __u32 hook;
 614                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 615                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 616         }
 617
 618         if (tb[TCA_IPT_TARG] == NULL) {
 619                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 620                 return -1;
 621         } else {
 622                 struct iptables_target *m = NULL;
 623                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 624                 m = get_target_name(t->u.user.name);
 625                 if (NULL != m) {
 626                         if (0 > build_st(m, t)) {
 627                                 fprintf(stderr, " %s error \n", m->name);
 628                                 return -1;
 629                         }
 630
 631                         opts =
 632                             merge_options(opts, m->extra_opts,
 633                                           &m->option_offset);
 634                 } else {
 635                         fprintf(stderr, " failed to find target %s\n\n",
 636                                 t->u.user.name);
 637                         return -1;
 638                 }
 639                 fprintf(f, "\ttarget ");
 640                 m->print(NULL, m->t, 0);
 641                 if (tb[TCA_IPT_INDEX] == NULL) {
 642                         fprintf(f, " [NULL ipt target index ]\n");
 643                 } else {
 644                         __u32 index;
 645                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 646                         fprintf(f, " \n\tindex %d", index);
 647                 }
 648
 649                 if (tb[TCA_IPT_CNT]) {
 650                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 651                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 652                 }
 653                 if (show_stats) {
 654                         if (tb[TCA_IPT_TM]) {
 655                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 656                                 print_tm(f,tm);
 657                         }
 658                 }
 659                 fprintf(f, " \n");
 660
 661         }
 662
 663         return 0;
 664 }
 665
 666 struct action_util ipt_action_util = {
 667         .id = "ipt",
 668         .parse_aopt = parse_ipt,
 669         .print_aopt = print_ipt,
 670 };
 671