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 static const char *pname = "tc-ipt";
  40 static const char *tname = "mangle";
  41 static const char *pversion = "0.1";
  42
  43 static const char *ipthooks[] = {
  44         "NF_IP_PRE_ROUTING",
  45         "NF_IP_LOCAL_IN",
  46         "NF_IP_FORWARD",
  47         "NF_IP_LOCAL_OUT",
  48         "NF_IP_POST_ROUTING",
  49 };
  50
  51 static struct option original_opts[] = {
  52         {"jump", 1, 0, 'j'},
  53         {0, 0, 0, 0}
  54 };
  55
  56 static struct iptables_target *t_list = NULL;
  57 static struct option *opts = original_opts;
  58 static unsigned int global_option_offset = 0;
  59 #define OPTION_OFFSET 256
  60
  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(char *name)
 216 {
 217         void *handle;
 218         char *error;
 219         char *new_name, *lname;
 220         struct iptables_target *m;
 221
 222         char path[sizeof (IPT_LIB_DIR) + sizeof ("/libipt_.so") + strlen(name)];
 223
 224         new_name = malloc(strlen(name) + 1);
 225         lname = malloc(strlen(name) + 1);
 226         if (new_name)
 227                 memset(new_name, '\0', strlen(name) + 1);
 228         else
 229                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 230
 231         if (lname)
 232                 memset(lname, '\0', strlen(name) + 1);
 233         else
 234                 exit_error(PARAMETER_PROBLEM, "get_target_name");
 235
 236         strcpy(new_name, name);
 237         strcpy(lname, name);
 238
 239         if (isupper(lname[0])) {
 240                 int i;
 241                 for (i = 0; i < strlen(name); i++) {
 242                         lname[i] = tolower(lname[i]);
 243                 }
 244         }
 245
 246         if (islower(new_name[0])) {
 247                 int i;
 248                 for (i = 0; i < strlen(new_name); i++) {
 249                         new_name[i] = toupper(new_name[i]);
 250                 }
 251         }
 252
 253         sprintf(path, IPT_LIB_DIR "/libipt_%s.so", new_name);
 254         handle = dlopen(path, RTLD_LAZY);
 255         if (!handle) {
 256                 sprintf(path, IPT_LIB_DIR "/libipt_%s.so", lname);
 257                 handle = dlopen(path, RTLD_LAZY);
 258                 if (!handle) {
 259                         fputs(dlerror(), stderr);
 260                         printf("\n");
 261                         return NULL;
 262                 }
 263         }
 264
 265         m = dlsym(handle, new_name);
 266         if ((error = dlerror()) != NULL) {
 267                 m = (struct iptables_target *) dlsym(handle, lname);
 268                 if ((error = dlerror()) != NULL) {
 269                         m = find_t(new_name);
 270                         if (NULL == m) {
 271                                 m = find_t(lname);
 272                                 if (NULL == m) {
 273                                         fputs(error, stderr);
 274                                         fprintf(stderr, "\n");
 275                                         dlclose(handle);
 276                                         return NULL;
 277                                 }
 278                         }
 279                 }
 280         }
 281
 282         return m;
 283 }
 284
 285
 286 struct in_addr *dotted_to_addr(const char *dotted)
 287 {
 288         static struct in_addr addr;
 289         unsigned char *addrp;
 290         char *p, *q;
 291         unsigned int onebyte;
 292         int i;
 293         char buf[20];
 294
 295         /* copy dotted string, because we need to modify it */
 296         strncpy(buf, dotted, sizeof (buf) - 1);
 297         addrp = (unsigned char *) &(addr.s_addr);
 298
 299         p = buf;
 300         for (i = 0; i < 3; i++) {
 301                 if ((q = strchr(p, '.')) == NULL)
 302                         return (struct in_addr *) NULL;
 303
 304                 *q = '\0';
 305                 if (string_to_number(p, 0, 255, &onebyte) == -1)
 306                         return (struct in_addr *) NULL;
 307
 308                 addrp[i] = (unsigned char) onebyte;
 309                 p = q + 1;
 310         }
 311
 312         /* we've checked 3 bytes, now we check the last one */
 313         if (string_to_number(p, 0, 255, &onebyte) == -1)
 314                 return (struct in_addr *) NULL;
 315
 316         addrp[3] = (unsigned char) onebyte;
 317
 318         return &addr;
 319 }
 320
 321 static void set_revision(char *name, u_int8_t revision)
 322 {
 323         /* Old kernel sources don't have ".revision" field,
 324         *  but we stole a byte from name. */
 325         name[IPT_FUNCTION_MAXNAMELEN - 2] = '\0';
 326         name[IPT_FUNCTION_MAXNAMELEN - 1] = revision;
 327 }
 328
 329 /*
 330  * we may need to check for version mismatch
 331 */
 332 int
 333 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 334 {
 335         unsigned int nfcache = 0;
 336
 337         if (target) {
 338                 size_t size;
 339
 340                 size =
 341                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 342
 343                 if (NULL == t) {
 344                         target->t = fw_calloc(1, size);
 345                         target->t->u.target_size = size;
 346
 347                         if (target->init != NULL)
 348                                 target->init(target->t, &nfcache);
 349                         set_revision(target->t->u.user.name, target->revision);
 350                 } else {
 351                         target->t = t;
 352                 }
 353                 strcpy(target->t->u.user.name, target->name);
 354                 return 0;
 355         }
 356
 357         return -1;
 358 }
 359
 360 static int parse_ipt(struct action_util *a,int *argc_p,
 361                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 362 {
 363         struct iptables_target *m = NULL;
 364         struct ipt_entry fw;
 365         struct rtattr *tail;
 366         int c;
 367         int rargc = *argc_p;
 368         char **argv = *argv_p;
 369         int argc = 0, iargc = 0;
 370         char k[16];
 371         int res = -1;
 372         int size = 0;
 373         int iok = 0, ok = 0;
 374         __u32 hook = 0, index = 0;
 375         res = 0;
 376
 377         {
 378                 int i;
 379                 for (i = 0; i < rargc; i++) {
 380                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 381                                 break;
 382                         }
 383                 }
 384                 iargc = argc = i;
 385         }
 386
 387         if (argc <= 2) {
 388                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 389                 return -1;
 390         }
 391
 392         while (1) {
 393                 c = getopt_long(argc, argv, "j:", opts, NULL);
 394                 if (c == -1)
 395                         break;
 396                 switch (c) {
 397                 case 'j':
 398                         m = get_target_name(optarg);
 399                         if (NULL != m) {
 400
 401                                 if (0 > build_st(m, NULL)) {
 402                                         printf(" %s error \n", m->name);
 403                                         return -1;
 404                                 }
 405                                 opts =
 406                                     merge_options(opts, m->extra_opts,
 407                                                   &m->option_offset);
 408                         } else {
 409                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 410                                 return -1;
 411                         }
 412                         ok++;
 413                         break;
 414
 415                 default:
 416                         memset(&fw, 0, sizeof (fw));
 417                         if (m) {
 418                                 m->parse(c - m->option_offset, argv, 0,
 419                                          &m->tflags, NULL, &m->t);
 420                         } else {
 421                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 422                                 return -1;
 423
 424                         }
 425                         ok++;
 426                         break;
 427
 428                 }
 429         }
 430
 431         if (iargc > optind) {
 432                 if (matches(argv[optind], "index") == 0) {
 433                         if (get_u32(&index, argv[optind + 1], 10)) {
 434                                 fprintf(stderr, "Illegal \"index\"\n");
 435                                 free_opts(opts);
 436                                 return -1;
 437                         }
 438                         iok++;
 439
 440                         optind += 2;
 441                 }
 442         }
 443
 444         if (!ok && !iok) {
 445                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 446                 return -1;
 447         }
 448
 449         /* check that we passed the correct parameters to the target */
 450         if (m)
 451                 m->final_check(m->tflags);
 452
 453         {
 454                 struct tcmsg *t = NLMSG_DATA(n);
 455                 if (t->tcm_parent != TC_H_ROOT
 456                     && t->tcm_parent == TC_H_MAJ(TC_H_INGRESS)) {
 457                         hook = NF_IP_PRE_ROUTING;
 458                 } else {
 459                         hook = NF_IP_POST_ROUTING;
 460                 }
 461         }
 462
 463         tail = NLMSG_TAIL(n);
 464         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 465         fprintf(stdout, "tablename: %s hook: %s\n ", tname, ipthooks[hook]);
 466         fprintf(stdout, "\ttarget: ");
 467
 468         if (m)
 469                 m->print(NULL, m->t, 0);
 470         fprintf(stdout, " index %d\n", index);
 471
 472         if (strlen(tname) > 16) {
 473                 size = 16;
 474                 k[15] = 0;
 475         } else {
 476                 size = 1 + strlen(tname);
 477         }
 478         strncpy(k, tname, size);
 479
 480         addattr_l(n, MAX_MSG, TCA_IPT_TABLE, k, size);
 481         addattr_l(n, MAX_MSG, TCA_IPT_HOOK, &hook, 4);
 482         addattr_l(n, MAX_MSG, TCA_IPT_INDEX, &index, 4);
 483         if (m)
 484                 addattr_l(n, MAX_MSG, TCA_IPT_TARG, m->t, m->t->u.target_size);
 485         tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
 486
 487         argc -= optind;
 488         argv += optind;
 489         *argc_p = rargc - iargc;
 490         *argv_p = argv;
 491
 492         optind = 1;
 493         free_opts(opts);
 494
 495         return 0;
 496
 497 }
 498
 499 static int
 500 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 501 {
 502         struct rtattr *tb[TCA_IPT_MAX + 1];
 503         struct ipt_entry_target *t = NULL;
 504
 505         if (arg == NULL)
 506                 return -1;
 507
 508         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 509
 510         if (tb[TCA_IPT_TABLE] == NULL) {
 511                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 512         } else {
 513                 fprintf(f, "tablename: %s ",
 514                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 515         }
 516
 517         if (tb[TCA_IPT_HOOK] == NULL) {
 518                 fprintf(f, "[NULL ipt hook name ]\n ");
 519                 return -1;
 520         } else {
 521                 __u32 hook;
 522                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 523                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 524         }
 525
 526         if (tb[TCA_IPT_TARG] == NULL) {
 527                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 528                 return -1;
 529         } else {
 530                 struct iptables_target *m = NULL;
 531                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 532                 m = get_target_name(t->u.user.name);
 533                 if (NULL != m) {
 534                         if (0 > build_st(m, t)) {
 535                                 fprintf(stderr, " %s error \n", m->name);
 536                                 return -1;
 537                         }
 538
 539                         opts =
 540                             merge_options(opts, m->extra_opts,
 541                                           &m->option_offset);
 542                 } else {
 543                         fprintf(stderr, " failed to find target %s\n\n",
 544                                 t->u.user.name);
 545                         return -1;
 546                 }
 547                 fprintf(f, "\ttarget ");
 548                 m->print(NULL, m->t, 0);
 549                 if (tb[TCA_IPT_INDEX] == NULL) {
 550                         fprintf(f, " [NULL ipt target index ]\n");
 551                 } else {
 552                         __u32 index;
 553                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 554                         fprintf(f, " \n\tindex %d", index);
 555                 }
 556
 557                 if (tb[TCA_IPT_CNT]) {
 558                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 559                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 560                 }
 561                 if (show_stats) {
 562                         if (tb[TCA_IPT_TM]) {
 563                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 564                                 print_tm(f,tm);
 565                         }
 566                 }
 567                 fprintf(f, " \n");
 568
 569         }
 570         free_opts(opts);
 571
 572         return 0;
 573 }
 574
 575 struct action_util ipt_action_util = {
 576         .id = "ipt",
 577         .parse_aopt = parse_ipt,
 578         .print_aopt = print_ipt,
 579 };
 580