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 int
 341 build_st(struct iptables_target *target, struct ipt_entry_target *t)
 342 {
 343         unsigned int nfcache = 0;
 344
 345         if (target) {
 346                 size_t size;
 347
 348                 size =
 349                     IPT_ALIGN(sizeof (struct ipt_entry_target)) + target->size;
 350
 351                 if (NULL == t) {
 352                         target->t = fw_calloc(1, size);
 353                         target->init(target->t, &nfcache);
 354                         target->t->u.target_size = size;
 355                 } else {
 356                         target->t = t;
 357                 }
 358                 strcpy(target->t->u.user.name, target->name);
 359                 return 0;
 360         }
 361
 362         return -1;
 363 }
 364
 365 static int parse_ipt(struct action_util *a,int *argc_p,
 366                      char ***argv_p, int tca_id, struct nlmsghdr *n)
 367 {
 368         struct iptables_target *m = NULL;
 369         struct ipt_entry fw;
 370         struct rtattr *tail;
 371         int c;
 372         int rargc = *argc_p;
 373         char **argv = *argv_p;
 374         struct option *opts;
 375         int argc = 0, iargc = 0;
 376         char k[16];
 377         int res = -1;
 378         int size = 0;
 379         int iok = 0, ok = 0;
 380         __u32 hook = 0, index = 0;
 381         res = 0;
 382
 383         {
 384                 int i;
 385                 for (i = 0; i < rargc; i++) {
 386                         if (NULL == argv[i] || 0 == strcmp(argv[i], "action")) {
 387                                 break;
 388                         }
 389                 }
 390                 iargc = argc = i;
 391         }
 392
 393         if (argc <= 2) {
 394                 fprintf(stderr,"bad arguements to ipt %d vs %d \n", argc, rargc);
 395                 return -1;
 396         }
 397
 398         opts = copy_options(original_opts);
 399
 400         if (NULL == opts)
 401                 return -1;
 402
 403         while (1) {
 404                 c = getopt_long(argc, argv, "j:", opts, NULL);
 405                 if (c == -1)
 406                         break;
 407                 switch (c) {
 408                 case 'j':
 409                         m = get_target_name(optarg);
 410                         if (NULL != m) {
 411
 412                                 if (0 > build_st(m, NULL)) {
 413                                         printf(" %s error \n", m->name);
 414                                         return -1;
 415                                 }
 416                                 opts =
 417                                     merge_options(opts, m->extra_opts,
 418                                                   &m->option_offset);
 419                         } else {
 420                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 421                                 return -1;
 422                         }
 423                         ok++;
 424                         break;
 425
 426                 default:
 427                         memset(&fw, 0, sizeof (fw));
 428                         if (m) {
 429                                 unsigned int fake_flags = 0;
 430                                 m->parse(c - m->option_offset, argv, 0,
 431                                          &fake_flags, NULL, &m->t);
 432                         } else {
 433                                 fprintf(stderr," failed to find target %s\n\n", optarg);
 434                                 return -1;
 435
 436                         }
 437                         ok++;
 438
 439                         /*m->final_check(m->t); -- Is this necessary?
 440                         ** useful when theres depencies
 441                         ** eg ipt_TCPMSS.c has have the TCP match loaded
 442                         ** before this can be used;
 443                         **  also seems the ECN target needs it
 444                         */
 445
 446                         break;
 447
 448                 }
 449         }
 450
 451         if (iargc > optind) {
 452                 if (matches(argv[optind], "index") == 0) {
 453                         if (get_u32(&index, argv[optind + 1], 10)) {
 454                                 fprintf(stderr, "Illegal \"index\"\n");
 455                                 return -1;
 456                         }
 457                         iok++;
 458
 459                         optind += 2;
 460                 }
 461         }
 462
 463         if (!ok && !iok) {
 464                 fprintf(stderr," ipt Parser BAD!! (%s)\n", *argv);
 465                 return -1;
 466         }
 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
 509         return 0;
 510
 511 }
 512
 513 static int
 514 print_ipt(struct action_util *au,FILE * f, struct rtattr *arg)
 515 {
 516         struct rtattr *tb[TCA_IPT_MAX + 1];
 517         struct ipt_entry_target *t = NULL;
 518         struct option *opts;
 519
 520         if (arg == NULL)
 521                 return -1;
 522
 523         opts = copy_options(original_opts);
 524
 525         if (NULL == opts)
 526                 return -1;
 527
 528         parse_rtattr_nested(tb, TCA_IPT_MAX, arg);
 529
 530         if (tb[TCA_IPT_TABLE] == NULL) {
 531                 fprintf(f, "[NULL ipt table name ] assuming mangle ");
 532         } else {
 533                 fprintf(f, "tablename: %s ",
 534                         (char *) RTA_DATA(tb[TCA_IPT_TABLE]));
 535         }
 536
 537         if (tb[TCA_IPT_HOOK] == NULL) {
 538                 fprintf(f, "[NULL ipt hook name ]\n ");
 539                 return -1;
 540         } else {
 541                 __u32 hook;
 542                 hook = *(__u32 *) RTA_DATA(tb[TCA_IPT_HOOK]);
 543                 fprintf(f, " hook: %s \n", ipthooks[hook]);
 544         }
 545
 546         if (tb[TCA_IPT_TARG] == NULL) {
 547                 fprintf(f, "\t[NULL ipt target parameters ] \n");
 548                 return -1;
 549         } else {
 550                 struct iptables_target *m = NULL;
 551                 t = RTA_DATA(tb[TCA_IPT_TARG]);
 552                 m = get_target_name(t->u.user.name);
 553                 if (NULL != m) {
 554                         if (0 > build_st(m, t)) {
 555                                 fprintf(stderr, " %s error \n", m->name);
 556                                 return -1;
 557                         }
 558
 559                         opts =
 560                             merge_options(opts, m->extra_opts,
 561                                           &m->option_offset);
 562                 } else {
 563                         fprintf(stderr, " failed to find target %s\n\n",
 564                                 t->u.user.name);
 565                         return -1;
 566                 }
 567                 fprintf(f, "\ttarget ");
 568                 m->print(NULL, m->t, 0);
 569                 if (tb[TCA_IPT_INDEX] == NULL) {
 570                         fprintf(f, " [NULL ipt target index ]\n");
 571                 } else {
 572                         __u32 index;
 573                         index = *(__u32 *) RTA_DATA(tb[TCA_IPT_INDEX]);
 574                         fprintf(f, " \n\tindex %d", index);
 575                 }
 576
 577                 if (tb[TCA_IPT_CNT]) {
 578                         struct tc_cnt *c  = RTA_DATA(tb[TCA_IPT_CNT]);;
 579                         fprintf(f, " ref %d bind %d", c->refcnt, c->bindcnt);
 580                 }
 581                 if (show_stats) {
 582                         if (tb[TCA_IPT_TM]) {
 583                                 struct tcf_t *tm = RTA_DATA(tb[TCA_IPT_TM]);
 584                                 print_tm(f,tm);
 585                         }
 586                 }
 587                 fprintf(f, " \n");
 588
 589         }
 590
 591         return 0;
 592 }
 593
 594 struct action_util ipt_action_util = {
 595         .id = "ipt",
 596         .parse_aopt = parse_ipt,
 597         .print_aopt = print_ipt,
 598 };
 599