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
  76 void
  77 register_target(struct iptables_target *me)
  78 {
  79 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  80 */
  81         me->next = t_list;
  82         t_list = me;
  83
  84 }
  85
  86 void
  87 exit_tryhelp(int status)
  88 {
  89         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  90                 pname, pname);
  91         exit(status);
  92 }
  93
  94 void
  95 exit_error(enum exittype status, char *msg, ...)
  96 {
  97         va_list args;
  98
  99         va_start(args, msg);
 100         fprintf(stderr, "%s v%s: ", pname, pversion);
 101         vfprintf(stderr, msg, args);
 102         va_end(args);
 103         fprintf(stderr, "\n");
 104         if (status == PARAMETER_PROBLEM)
 105                 exit_tryhelp(status);
 106         if (status == VERSION_PROBLEM)
 107                 fprintf(stderr,
 108                         "Perhaps iptables or your kernel needs to be upgraded.\n");
 109         exit(status);
 110 }
 111
 112 /* stolen from iptables 1.2.11
 113 They should really have them as a library so i can link to them
 114 Email them next time i remember
 115 */
 116
 117 char *
 118 addr_to_dotted(const struct in_addr *addrp)
 119 {
 120         static char buf[20];
 121         const unsigned char *bytep;
 122
 123         bytep = (const unsigned char *) &(addrp->s_addr);
 124         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 125         return buf;
 126 }
 127
 128 int string_to_number_ll(const char *s, unsigned long long min,
 129                         unsigned long long max,
 130                  unsigned long long *ret)
 131 {
 132         unsigned long long number;
 133         char *end;
 134
 135         /* Handle hex, octal, etc. */
 136         errno = 0;
 137         number = strtoull(s, &end, 0);
 138         if (*end == '\0' && end != s) {
 139                 /* we parsed a number, let's see if we want this */
 140                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 141                         *ret = number;
 142                         return 0;
 143                 }
 144         }
 145         return -1;
 146 }
 147
 148 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 149                        unsigned long *ret)
 150 {
 151         int result;
 152         unsigned long long number;
 153
 154         result = string_to_number_ll(s, min, max, &number);
 155         *ret = (unsigned long)number;
 156
 157         return result;
 158 }
 159
 160 int string_to_number(const char *s, unsigned int min, unsigned int max,
 161                 unsigned int *ret)
 162 {
 163         int result;
 164         unsigned long number;
 165
 166         result = string_to_number_l(s, min, max, &number);
 167         *ret = (unsigned int)number;
 168
 169         return result;
 170 }
 171
 172 static struct option *
 173 copy_options(struct option *oldopts)
 174 {
 175         struct option *merge;
 176         unsigned int num_old;
 177         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 178         merge = malloc(sizeof (struct option) * (num_old + 1));
 179         if (NULL == merge)
 180                 return NULL;
 181         memcpy(merge, oldopts, num_old * sizeof (struct option));
 182         memset(merge + num_old, 0, sizeof (struct option));
 183         return merge;
 184 }
 185
 186 static struct option *
 187 merge_options(struct option *oldopts, const struct option *newopts,
 188               unsigned int *option_offset)
 189 {
 190         struct option *merge;
 191         unsigned int num_old, num_new, i;
 192
 193         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 194         for (num_new = 0; newopts[num_new].name; num_new++) ;
 195
 196         *option_offset = global_option_offset + OPTION_OFFSET;
 197
 198         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 199         memcpy(merge, oldopts, num_old * sizeof (struct option));
 200         for (i = 0; i < num_new; i++) {
 201                 merge[num_old + i] = newopts[i];
 202                 merge[num_old + i].val += *option_offset;
 203         }
 204         memset(merge + num_old + num_new, 0, sizeof (struct option));
 205
 206         return merge;
 207 }
 208
 209 static void *
 210 fw_calloc(size_t count, size_t size)
 211 {
 212         void *p;
 213
 214         if ((p = (void *) calloc(count, size)) == NULL) {
 215                 perror("iptables: calloc failed");
 216                 exit(1);
 217         }
 218         return p;
 219 }
 220
 221 static struct iptables_target *
 222 find_t(char *name)
 223 {
 224         struct iptables_target *m;
 225         for (m = t_list; m; m = m->next) {
 226                 if (strcmp(m->name, name) == 0)
 227                         return m;
 228         }
 229
 230         return NULL;
 231 }
 232
 233 static struct iptables_target *
 234 get_target_name(char *name)
 235 {
 236         void *handle;
 237         char *error;
 238         char *new_name, *lname;
 239         struct iptables_target *m;
 240
 241         char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
 242
 243         new_name = malloc(strlen(name) + 1);
 244         lname = malloc(strlen(name) + 1);
 245         if (new_name)
 246                 memset(new_name, '\0', strlen(name) + 1);
 247         else
 248                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 249
 250         if (lname)
 251                 memset(lname, '\0', strlen(name) + 1);
 252         else
 253                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 254
 255         strcpy(new_name, name);
 256         strcpy(lname, name);
 257
 258         if (isupper(lname[0])) {
 259                 int i;
 260                 for (i = 0; i < strlen(name); i++) {
 261                         lname[i] = tolower(lname[i]);
 262                 }
 263         }
 264
 265         if (islower(new_name[0])) {
 266                 int i;
 267                 for (i = 0; i < strlen(new_name); i++) {
 268                         new_name[i] = toupper(new_name[i]);
 269                 }
 270         }
 271
 272         sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
 273         handle = dlopen(path, RTLD_LAZY);
 274         if (!handle) {
 275                 sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
 276                 handle = dlopen(path, RTLD_LAZY);
 277                 if (!handle) {
 278                         fputs(dlerror(), stderr);
 279                         printf("\n");
 280                         return NULL;
 281                 }
 282         }
 283
 284         m = dlsym(handle, new_name);
 285         if ((error = dlerror()) != NULL) {
 286                 m = (struct iptables_target *) dlsym(handle, lname);
 287                 if ((error = dlerror()) != NULL) {
 288                         m = find_t(new_name);
 289                         if (NULL == m) {
 290                                 m = find_t(lname);
 291                                 if (NULL == m) {
 292                                         fputs(error, stderr);
 293                                         fprintf(stderr, "\n");
 294                                         dlclose(handle);
 295                                         return NULL;
 296                                 }
 297                         }
 298                 }
 299         }
 300
 301         return m;
 302 }
 303
 304
 305 struct in_addr *dotted_to_addr(const char *dotted)
 306 {
 307         static struct in_addr addr;
 308         unsigned char *addrp;
 309         char *p, *q;
 310         unsigned int onebyte;
 311         int i;
 312         char buf[20];
 313
 314         /* copy dotted string, because we need to modify it */
 315         strncpy(buf, dotted, sizeof (buf) - 1);
 316         addrp = (unsigned char *) &(addr.s_addr);
 317
 318         p = buf;
 319         for (i = 0; i < 3; i++) {
 320                 if ((q = strchr(p, '.')) == NULL)
 321                         return (struct in_addr *) NULL;
 322
 323                 *q = '\0';
 324                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 325                         return (struct in_addr *) NULL;
 326
 327                 addrp[i] = (unsigned char) onebyte;
 328                 p = q + 1;
 329         }
 330
 331         /* we've checked 3 bytes, now we check the last one */
 332         if (string_to_number(p, 0, 255, &onebyte) == -1)
 333                 return (struct in_addr *) NULL;
 334
 335         addrp[3] = (unsigned char) onebyte;
 336
 337         return &addr;
 338 }
 339
 340 static void set_revision(char *name, u_int8_t revision)
 341 {
 342         /* Old kernel sources don't have ".revision" field,
 343         *  but we stole a byte from name. */
 344         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 345         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 346 }
 347
 348 /*
 349  * we may need to check for version mismatch
 350 */
 351 int
 352 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 353 {
 354         unsigned int nfcache = 0;
 355
 356         if (target) {
 357                 size_t size;
 358
 359                 size =
 360                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 361
 362                 if (NULL == t) {
 363                         target->t = fw_calloc(1, size);
 364                         target->t->u.target_size = size;
 365
 366                         if (target->init != NULL)
 367                                 target->init(target->t, &nfcache);
 368                         set_revision(target->t->u.user.name, target->revision);
 369                 } else {
 370                         target->t = t;
 371                 }
 372                 strcpy(target->t->u.user.name, target->name);
 373                 return 0;
 374         }
 375
 376         return -1;
 377 }
 378
 379 static int parse_ipt(struct action_util *a,int *argc_p,
 380                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 381 {
 382         struct iptables_target *m = NULL;
 383         struct ipt_entry fw;
 384         struct rtattr *tail;
 385         int c;
 386         int rargc = *argc_p;
 387         char **argv = *argv_p;
 388         struct option *opts;
 389         int argc = 0, iargc = 0;
 390         char k[16];
 391         int res = -1;
 392         int size = 0;
 393         int iok = 0, ok = 0;
 394         __u32 hook = 0, index = 0;
 395         res = 0;
 396
 397         {
 398                 int i;
 399                 for (i = 0; i < rargc; i++) {
 400                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 401                                 break;
 402                         }
 403                 }
 404                 iargc = argc = i;
 405         }
 406
 407         if (argc <= 2) {
 408                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 409                 return -1;
 410         }
 411
 412         opts = copy_options(original_opts);
 413
 414         if (NULL == opts)
 415                 return -1;
 416
 417         while (1) {
 418                 c = getopt_long(argc, argv, "j:", opts, NULL);
 419                 if (c == -1)
 420                         break;
 421                 switch (c) {
 422                 case 'j':
 423                         m = get_target_name(optarg);
 424                         if (NULL != m) {
 425
 426                                 if (0 > build_st(m, NULL)) {
 427                                         printf(" %s error \n", m->name);
 428                                         return -1;
 429                                 }
 430                                 opts =
 431                                     merge_options(opts, m->extra_opts,
 432                                                   &m->option_offset);
 433                         } else {
 434                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 435                                 return -1;
 436                         }
 437                         ok++;
 438                         break;
 439
 440                 default:
 441                         memset(&fw, 0, sizeof (fw));
 442                         if (m) {
 443                                 unsigned int fake_flags = 0;
 444                                 m->parse(c - m->option_offset, argv, 0,
 445                                          &fake_flags, NULL, &m->t);
 446                         } else {
 447                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 448                                 return -1;
 449
 450                         }
 451                         ok++;
 452
 453                         /*m->final_check(m->t); -- Is this necessary?
 454                         ** useful when theres depencies
 455                         ** eg ipt_TCPMSS.c has have the TCP match loaded
 456                         ** before this can be used;
 457                         **  also seems the ECN target needs it
 458                         */
 459
 460                         break;
 461
 462                 }
 463         }
 464
 465         if (iargc > optind) {
 466                 if (matches(argv[optind], "index") == 0) {
 467                         if (get_u32(&index, argv[optind + 1], 10)) {
 468                                 fprintf(stderr, "Illegal \"index\"\n");
 469                                 return -1;
 470                         }
 471                         iok++;
 472
 473                         optind += 2;
 474                 }
 475         }
 476
 477         if (!ok && !iok) {
 478                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 479                 return -1;
 480         }
 481
 482         {
 483                 struct tcmsg *t = NLMSG_DATA(n);
 484                 if (t->tcm_parent != TC_H_ROOT
 485                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 486                         hook = NF_IP_PRE_ROUTING;
 487                 } else {
 488                         hook = NF_IP_POST_ROUTING;
 489                 }
 490         }
 491
 492         tail = NLMSG_TAIL(n);
 493         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 494         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 495         fprintf(stdout, "\ttarget: ");
 496
 497         if (m)
 498                 m->print(NULL, m->t, 0);
 499         fprintf(stdout, " index %d\n", index);
 500
 501         if (strlen(tname) > 16) {
 502                 size = 16;
 503                 k[15] = 0;
 504         } else {
 505                 size = 1 + strlen(tname);
 506         }
 507         strncpy(k, tname, size);
 508
 509         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 510         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 511         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 512         if (m)
 513                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 514         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 515
 516         argc -= optind;
 517         argv += optind;
 518         *argc_p = rargc - iargc;
 519         *argv_p = argv;
 520
 521         optind = 1;
 522
 523         return 0;
 524
 525 }
 526
 527 static int
 528 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 529 {
 530         struct rtattr *tb[TCA_IPT_MAX + 1];
 531         struct ipt_entry_target *t = NULL;
 532         struct option *opts;
 533
 534         if (arg == NULL)
 535                 return -1;
 536
 537         opts = copy_options(original_opts);
 538
 539         if (NULL == opts)
 540                 return -1;
 541
 542         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 543
 544         if (tb[TCA_IPT_TABLE] == NULL) {
 545                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 546         } else {
 547                 fprintf(f, "tablename: %s ",
 548                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 549         }
 550
 551         if (tb[TCA_IPT_HOOK] == NULL) {
 552                 fprintf(f, "[NULL ipt hook name ]\n ");
 553                 return -1;
 554         } else {
 555                 __u32 hook;
 556                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 557                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 558         }
 559
 560         if (tb[TCA_IPT_TARG] == NULL) {
 561                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 562                 return -1;
 563         } else {
 564                 struct iptables_target *m = NULL;
 565                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 566                 m = get_target_name(t->u.user.name);
 567                 if (NULL != m) {
 568                         if (0 > build_st(m, t)) {
 569                                 fprintf(stderr, " %s error \n", m->name);
 570                                 return -1;
 571                         }
 572
 573                         opts =
 574                             merge_options(opts, m->extra_opts,
 575                                           &m->option_offset);
 576                 } else {
 577                         fprintf(stderr, " failed to find target %s\n\n",
 578                                 t->u.user.name);
 579                         return -1;
 580                 }
 581                 fprintf(f, "\ttarget ");
 582                 m->print(NULL, m->t, 0);
 583                 if (tb[TCA_IPT_INDEX] == NULL) {
 584                         fprintf(f, " [NULL ipt target index ]\n");
 585                 } else {
 586                         __u32 index;
 587                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 588                         fprintf(f, " \n\tindex %d", index);
 589                 }
 590
 591                 if (tb[TCA_IPT_CNT]) {
 592                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 593                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 594                 }
 595                 if (show_stats) {
 596                         if (tb[TCA_IPT_TM]) {
 597                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 598                                 print_tm(f,tm);
 599                         }
 600                 }
 601                 fprintf(f, " \n");
 602
 603         }
 604
 605         return 0;
 606 }
 607
 608 struct action_util ipt_action_util = {
 609         .id = "ipt",
 610         .parse_aopt = parse_ipt,
 611         .print_aopt = print_ipt,
 612 };
 613