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 struct option *opts = original_opts;
  73 static unsigned int global_option_offset = 0;
  74 #define OPTION_OFFSET 256
  75
  76
  77 void
  78 register_target(struct iptables_target *me)
  79 {
  80 /*      fprintf(stderr, "\nDummy register_target %s \n", me->name);
  81 */
  82         me->next = t_list;
  83         t_list = me;
  84
  85 }
  86
  87 void
  88 exit_tryhelp(int status)
  89 {
  90         fprintf(stderr, "Try `%s -h' or '%s --help' for more information.\n",
  91                 pname, pname);
  92         exit(status);
  93 }
  94
  95 void
  96 exit_error(enum exittype status, char *msg, ...)
  97 {
  98         va_list args;
  99
 100         va_start(args, msg);
 101         fprintf(stderr, "%s v%s: ", pname, pversion);
 102         vfprintf(stderr, msg, args);
 103         va_end(args);
 104         fprintf(stderr, "\n");
 105         if (status == PARAMETER_PROBLEM)
 106                 exit_tryhelp(status);
 107         if (status == VERSION_PROBLEM)
 108                 fprintf(stderr,
 109                         "Perhaps iptables or your kernel needs to be upgraded.\n");
 110         exit(status);
 111 }
 112
 113 /* stolen from iptables 1.2.11
 114 They should really have them as a library so i can link to them
 115 Email them next time i remember
 116 */
 117
 118 char *
 119 addr_to_dotted(const struct in_addr *addrp)
 120 {
 121         static char buf[20];
 122         const unsigned char *bytep;
 123
 124         bytep = (const unsigned char *) &(addrp->s_addr);
 125         sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);
 126         return buf;
 127 }
 128
 129 int string_to_number_ll(const char *s, unsigned long long min,
 130                         unsigned long long max,
 131                  unsigned long long *ret)
 132 {
 133         unsigned long long number;
 134         char *end;
 135
 136         /* Handle hex, octal, etc. */
 137         errno = 0;
 138         number = strtoull(s, &end, 0);
 139         if (*end == '\0' && end != s) {
 140                 /* we parsed a number, let's see if we want this */
 141                 if (errno != ERANGE && min <= number && (!max || number <= max)) {
 142                         *ret = number;
 143                         return 0;
 144                 }
 145         }
 146         return -1;
 147 }
 148
 149 int string_to_number_l(const char *s, unsigned long min, unsigned long max,
 150                        unsigned long *ret)
 151 {
 152         int result;
 153         unsigned long long number;
 154
 155         result = string_to_number_ll(s, min, max, &number);
 156         *ret = (unsigned long)number;
 157
 158         return result;
 159 }
 160
 161 int string_to_number(const char *s, unsigned int min, unsigned int max,
 162                 unsigned int *ret)
 163 {
 164         int result;
 165         unsigned long number;
 166
 167         result = string_to_number_l(s, min, max, &number);
 168         *ret = (unsigned int)number;
 169
 170         return result;
 171 }
 172
 173 static void free_opts(struct option *opts)
 174 {
 175         if (opts != original_opts) {
 176                 free(opts);
 177                 opts = original_opts;
 178                 global_option_offset = 0;
 179         }
 180 }
 181
 182 static struct option *
 183 merge_options(struct option *oldopts, const struct option *newopts,
 184               unsigned int *option_offset)
 185 {
 186         struct option *merge;
 187         unsigned int num_old, num_new, i;
 188
 189         for (num_old = 0; oldopts[num_old].name; num_old++) ;
 190         for (num_new = 0; newopts[num_new].name; num_new++) ;
 191
 192         *option_offset = global_option_offset + OPTION_OFFSET;
 193
 194         merge = malloc(sizeof (struct option) * (num_new + num_old + 1));
 195         memcpy(merge, oldopts, num_old * sizeof (struct option));
 196         for (i = 0; i < num_new; i++) {
 197                 merge[num_old + i] = newopts[i];
 198                 merge[num_old + i].val += *option_offset;
 199         }
 200         memset(merge + num_old + num_new, 0, sizeof (struct option));
 201
 202         return merge;
 203 }
 204
 205 static void *
 206 fw_calloc(size_t count, size_t size)
 207 {
 208         void *p;
 209
 210         if ((p = (void *) calloc(count, size)) == NULL) {
 211                 perror("iptables: calloc failed");
 212                 exit(1);
 213         }
 214         return p;
 215 }
 216
 217 static struct iptables_target *
 218 find_t(char *name)
 219 {
 220         struct iptables_target *m;
 221         for (m = t_list; m; m = m->next) {
 222                 if (strcmp(m->name, name) == 0)
 223                         return m;
 224         }
 225
 226         return NULL;
 227 }
 228
 229 static struct iptables_target *
 230 get_target_name(char *name)
 231 {
 232         void *handle;
 233         char *error;
 234         char *new_name, *lname;
 235         struct iptables_target *m;
 236
 237         char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
 238
 239         new_name = malloc(strlen(name) + 1);
 240         lname = malloc(strlen(name) + 1);
 241         if (new_name)
 242                 memset(new_name, '\0', strlen(name) + 1);
 243         else
 244                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 245
 246         if (lname)
 247                 memset(lname, '\0', strlen(name) + 1);
 248         else
 249                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 250
 251         strcpy(new_name, name);
 252         strcpy(lname, name);
 253
 254         if (isupper(lname[0])) {
 255                 int i;
 256                 for (i = 0; i < strlen(name); i++) {
 257                         lname[i] = tolower(lname[i]);
 258                 }
 259         }
 260
 261         if (islower(new_name[0])) {
 262                 int i;
 263                 for (i = 0; i < strlen(new_name); i++) {
 264                         new_name[i] = toupper(new_name[i]);
 265                 }
 266         }
 267
 268         sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
 269         handle = dlopen(path, RTLD_LAZY);
 270         if (!handle) {
 271                 sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
 272                 handle = dlopen(path, RTLD_LAZY);
 273                 if (!handle) {
 274                         fputs(dlerror(), stderr);
 275                         printf("\n");
 276                         return NULL;
 277                 }
 278         }
 279
 280         m = dlsym(handle, new_name);
 281         if ((error = dlerror()) != NULL) {
 282                 m = (struct iptables_target *) dlsym(handle, lname);
 283                 if ((error = dlerror()) != NULL) {
 284                         m = find_t(new_name);
 285                         if (NULL == m) {
 286                                 m = find_t(lname);
 287                                 if (NULL == m) {
 288                                         fputs(error, stderr);
 289                                         fprintf(stderr, "\n");
 290                                         dlclose(handle);
 291                                         return NULL;
 292                                 }
 293                         }
 294                 }
 295         }
 296
 297         return m;
 298 }
 299
 300
 301 struct in_addr *dotted_to_addr(const char *dotted)
 302 {
 303         static struct in_addr addr;
 304         unsigned char *addrp;
 305         char *p, *q;
 306         unsigned int onebyte;
 307         int i;
 308         char buf[20];
 309
 310         /* copy dotted string, because we need to modify it */
 311         strncpy(buf, dotted, sizeof (buf) - 1);
 312         addrp = (unsigned char *) &(addr.s_addr);
 313
 314         p = buf;
 315         for (i = 0; i < 3; i++) {
 316                 if ((q = strchr(p, '.')) == NULL)
 317                         return (struct in_addr *) NULL;
 318
 319                 *q = '\0';
 320                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 321                         return (struct in_addr *) NULL;
 322
 323                 addrp[i] = (unsigned char) onebyte;
 324                 p = q + 1;
 325         }
 326
 327         /* we've checked 3 bytes, now we check the last one */
 328         if (string_to_number(p, 0, 255, &onebyte) == -1)
 329                 return (struct in_addr *) NULL;
 330
 331         addrp[3] = (unsigned char) onebyte;
 332
 333         return &addr;
 334 }
 335
 336 static void set_revision(char *name, u_int8_t revision)
 337 {
 338         /* Old kernel sources don't have ".revision" field,
 339         *  but we stole a byte from name. */
 340         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 341         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 342 }
 343
 344 /*
 345  * we may need to check for version mismatch
 346 */
 347 int
 348 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 349 {
 350         unsigned int nfcache = 0;
 351
 352         if (target) {
 353                 size_t size;
 354
 355                 size =
 356                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 357
 358                 if (NULL == t) {
 359                         target->t = fw_calloc(1, size);
 360                         target->t->u.target_size = size;
 361
 362                         if (target->init != NULL)
 363                                 target->init(target->t, &nfcache);
 364                         set_revision(target->t->u.user.name, target->revision);
 365                 } else {
 366                         target->t = t;
 367                 }
 368                 strcpy(target->t->u.user.name, target->name);
 369                 return 0;
 370         }
 371
 372         return -1;
 373 }
 374
 375 static int parse_ipt(struct action_util *a,int *argc_p,
 376                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 377 {
 378         struct iptables_target *m = NULL;
 379         struct ipt_entry fw;
 380         struct rtattr *tail;
 381         int c;
 382         int rargc = *argc_p;
 383         char **argv = *argv_p;
 384         int argc = 0, iargc = 0;
 385         char k[16];
 386         int res = -1;
 387         int size = 0;
 388         int iok = 0, ok = 0;
 389         __u32 hook = 0, index = 0;
 390         res = 0;
 391
 392         {
 393                 int i;
 394                 for (i = 0; i < rargc; i++) {
 395                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 396                                 break;
 397                         }
 398                 }
 399                 iargc = argc = i;
 400         }
 401
 402         if (argc <= 2) {
 403                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 404                 return -1;
 405         }
 406
 407         while (1) {
 408                 c = getopt_long(argc, argv, "j:", opts, NULL);
 409                 if (c == -1)
 410                         break;
 411                 switch (c) {
 412                 case 'j':
 413                         m = get_target_name(optarg);
 414                         if (NULL != m) {
 415
 416                                 if (0 > build_st(m, NULL)) {
 417                                         printf(" %s error \n", m->name);
 418                                         return -1;
 419                                 }
 420                                 opts =
 421                                     merge_options(opts, m->extra_opts,
 422                                                   &m->option_offset);
 423                         } else {
 424                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 425                                 return -1;
 426                         }
 427                         ok++;
 428                         break;
 429
 430                 default:
 431                         memset(&fw, 0, sizeof (fw));
 432                         if (m) {
 433                                 m->parse(c - m->option_offset, argv, 0,
 434                                          &m->tflags, NULL, &m->t);
 435                         } else {
 436                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 437                                 return -1;
 438
 439                         }
 440                         ok++;
 441                         break;
 442
 443                 }
 444         }
 445
 446         if (iargc > optind) {
 447                 if (matches(argv[optind], "index") == 0) {
 448                         if (get_u32(&index, argv[optind + 1], 10)) {
 449                                 fprintf(stderr, "Illegal \"index\"\n");
 450                                 free_opts(opts);
 451                                 return -1;
 452                         }
 453                         iok++;
 454
 455                         optind += 2;
 456                 }
 457         }
 458
 459         if (!ok && !iok) {
 460                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 461                 return -1;
 462         }
 463
 464         /* check that we passed the correct parameters to the target */
 465         if (m)
 466                 m->final_check(m->tflags);
 467
 468         {
 469                 struct tcmsg *t = NLMSG_DATA(n);
 470                 if (t->tcm_parent != TC_H_ROOT
 471                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 472                         hook = NF_IP_PRE_ROUTING;
 473                 } else {
 474                         hook = NF_IP_POST_ROUTING;
 475                 }
 476         }
 477
 478         tail = NLMSG_TAIL(n);
 479         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 480         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 481         fprintf(stdout, "\ttarget: ");
 482
 483         if (m)
 484                 m->print(NULL, m->t, 0);
 485         fprintf(stdout, " index %d\n", index);
 486
 487         if (strlen(tname) > 16) {
 488                 size = 16;
 489                 k[15] = 0;
 490         } else {
 491                 size = 1 + strlen(tname);
 492         }
 493         strncpy(k, tname, size);
 494
 495         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 496         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 497         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 498         if (m)
 499                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 500         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 501
 502         argc -= optind;
 503         argv += optind;
 504         *argc_p = rargc - iargc;
 505         *argv_p = argv;
 506
 507         optind = 1;
 508         free_opts(opts);
 509
 510         return 0;
 511
 512 }
 513
 514 static int
 515 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 516 {
 517         struct rtattr *tb[TCA_IPT_MAX + 1];
 518         struct ipt_entry_target *t = NULL;
 519
 520         if (arg == NULL)
 521                 return -1;
 522
 523         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 524
 525         if (tb[TCA_IPT_TABLE] == NULL) {
 526                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 527         } else {
 528                 fprintf(f, "tablename: %s ",
 529                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 530         }
 531
 532         if (tb[TCA_IPT_HOOK] == NULL) {
 533                 fprintf(f, "[NULL ipt hook name ]\n ");
 534                 return -1;
 535         } else {
 536                 __u32 hook;
 537                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 538                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 539         }
 540
 541         if (tb[TCA_IPT_TARG] == NULL) {
 542                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 543                 return -1;
 544         } else {
 545                 struct iptables_target *m = NULL;
 546                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 547                 m = get_target_name(t->u.user.name);
 548                 if (NULL != m) {
 549                         if (0 > build_st(m, t)) {
 550                                 fprintf(stderr, " %s error \n", m->name);
 551                                 return -1;
 552                         }
 553
 554                         opts =
 555                             merge_options(opts, m->extra_opts,
 556                                           &m->option_offset);
 557                 } else {
 558                         fprintf(stderr, " failed to find target %s\n\n",
 559                                 t->u.user.name);
 560                         return -1;
 561                 }
 562                 fprintf(f, "\ttarget ");
 563                 m->print(NULL, m->t, 0);
 564                 if (tb[TCA_IPT_INDEX] == NULL) {
 565                         fprintf(f, " [NULL ipt target index ]\n");
 566                 } else {
 567                         __u32 index;
 568                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 569                         fprintf(f, " \n\tindex %d", index);
 570                 }
 571
 572                 if (tb[TCA_IPT_CNT]) {
 573                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 574                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 575                 }
 576                 if (show_stats) {
 577                         if (tb[TCA_IPT_TM]) {
 578                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 579                                 print_tm(f,tm);
 580                         }
 581                 }
 582                 fprintf(f, " \n");
 583
 584         }
 585         free_opts(opts);
 586
 587         return 0;
 588 }
 589
 590 struct action_util ipt_action_util = {
 591         .id = "ipt",
 592         .parse_aopt = parse_ipt,
 593         .print_aopt = print_ipt,
 594 };
 595