extensions/libip6t_rt.c

   1 /* Shared library add-on to ip6tables to add Routing header support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <getopt.h>
   7 #include <errno.h>
   8 #include <xtables.h>
   9 /*#include <linux/in6.h>*/
  10 #include <linux/netfilter_ipv6/ip6t_rt.h>
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #include <arpa/inet.h>
  14
  15 /*#define DEBUG 1*/
  16
  17 static void rt_help(void)
  18 {
  19         printf(
  20 "rt match options:\n"
  21 "[!] --rt-type type             match the type\n"
  22 "[!] --rt-segsleft num[:num]    match the Segments Left field (range)\n"
  23 "[!] --rt-len length            total length of this header\n"
  24 " --rt-0-res                    check the reserved filed, too (type 0)\n"
  25 " --rt-0-addrs ADDR[,ADDR...]   Type=0 addresses (list, max: %d)\n"
  26 " --rt-0-not-strict             List of Type=0 addresses not a strict list\n",
  27 IP6T_RT_HOPS);
  28 }
  29
  30 static const struct option rt_opts[] = {
  31         { "rt-type", 1, NULL, '1' },
  32         { "rt-segsleft", 1, NULL, '2' },
  33         { "rt-len", 1, NULL, '3' },
  34         { "rt-0-res", 0, NULL, '4' },
  35         { "rt-0-addrs", 1, NULL, '5' },
  36         { "rt-0-not-strict", 0, NULL, '6' },
  37         { .name = NULL }
  38 };
  39
  40 static u_int32_t
  41 parse_rt_num(const char *idstr, const char *typestr)
  42 {
  43         unsigned long int id;
  44         char* ep;
  45
  46         id =  strtoul(idstr,&ep,0) ;
  47
  48         if ( idstr == ep ) {
  49                 xtables_error(PARAMETER_PROBLEM,
  50                            "RT no valid digits in %s `%s'", typestr, idstr);
  51         }
  52         if ( id == ULONG_MAX  && errno == ERANGE ) {
  53                 xtables_error(PARAMETER_PROBLEM,
  54                            "%s `%s' specified too big: would overflow",
  55                            typestr, idstr);
  56         }
  57         if ( *idstr != '\0'  && *ep != '\0' ) {
  58                 xtables_error(PARAMETER_PROBLEM,
  59                            "RT error parsing %s `%s'", typestr, idstr);
  60         }
  61         return id;
  62 }
  63
  64 static void
  65 parse_rt_segsleft(const char *idstring, u_int32_t *ids)
  66 {
  67         char *buffer;
  68         char *cp;
  69
  70         buffer = strdup(idstring);
  71         if ((cp = strchr(buffer, ':')) == NULL)
  72                 ids[0] = ids[1] = parse_rt_num(buffer,"segsleft");
  73         else {
  74                 *cp = '\0';
  75                 cp++;
  76
  77                 ids[0] = buffer[0] ? parse_rt_num(buffer,"segsleft") : 0;
  78                 ids[1] = cp[0] ? parse_rt_num(cp,"segsleft") : 0xFFFFFFFF;
  79         }
  80         free(buffer);
  81 }
  82
  83 static char *
  84 addr_to_numeric(const struct in6_addr *addrp)
  85 {
  86         static char buf[50+1];
  87         return (char *)inet_ntop(AF_INET6, addrp, buf, sizeof(buf));
  88 }
  89
  90 static struct in6_addr *
  91 numeric_to_addr(const char *num)
  92 {
  93         static struct in6_addr ap;
  94         int err;
  95
  96         if ((err=inet_pton(AF_INET6, num, &ap)) == 1)
  97                 return &ap;
  98 #ifdef DEBUG
  99         fprintf(stderr, "\nnumeric2addr: %d\n", err);
 100 #endif
 101         xtables_error(PARAMETER_PROBLEM, "bad address: %s", num);
 102
 103         return (struct in6_addr *)NULL;
 104 }
 105
 106
 107 static int
 108 parse_addresses(const char *addrstr, struct in6_addr *addrp)
 109 {
 110         char *buffer, *cp, *next;
 111         unsigned int i;
 112
 113         buffer = strdup(addrstr);
 114         if (!buffer) xtables_error(OTHER_PROBLEM, "strdup failed");
 115
 116         for (cp=buffer, i=0; cp && i<IP6T_RT_HOPS; cp=next,i++)
 117         {
 118                 next=strchr(cp, ',');
 119                 if (next) *next++='\0';
 120                 memcpy(&(addrp[i]), numeric_to_addr(cp), sizeof(struct in6_addr));
 121 #if DEBUG
 122                 printf("addr str: %s\n", cp);
 123                 printf("addr ip6: %s\n", addr_to_numeric((numeric_to_addr(cp))));
 124                 printf("addr [%d]: %s\n", i, addr_to_numeric(&(addrp[i])));
 125 #endif
 126         }
 127         if (cp) xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
 128
 129         free(buffer);
 130
 131 #if DEBUG
 132         printf("addr nr: %d\n", i);
 133 #endif
 134
 135         return i;
 136 }
 137
 138 static void rt_init(struct xt_entry_match *m)
 139 {
 140         struct ip6t_rt *rtinfo = (struct ip6t_rt *)m->data;
 141
 142         rtinfo->rt_type = 0x0L;
 143         rtinfo->segsleft[0] = 0x0L;
 144         rtinfo->segsleft[1] = 0xFFFFFFFF;
 145         rtinfo->hdrlen = 0;
 146         rtinfo->flags = 0;
 147         rtinfo->invflags = 0;
 148         rtinfo->addrnr = 0;
 149 }
 150
 151 static int rt_parse(int c, char **argv, int invert, unsigned int *flags,
 152                     const void *entry, struct xt_entry_match **match)
 153 {
 154         struct ip6t_rt *rtinfo = (struct ip6t_rt *)(*match)->data;
 155
 156         switch (c) {
 157         case '1':
 158                 if (*flags & IP6T_RT_TYP)
 159                         xtables_error(PARAMETER_PROBLEM,
 160                                    "Only one `--rt-type' allowed");
 161                 xtables_check_inverse(optarg, &invert, &optind, 0);
 162                 rtinfo->rt_type = parse_rt_num(argv[optind-1], "type");
 163                 if (invert)
 164                         rtinfo->invflags |= IP6T_RT_INV_TYP;
 165                 rtinfo->flags |= IP6T_RT_TYP;
 166                 *flags |= IP6T_RT_TYP;
 167                 break;
 168         case '2':
 169                 if (*flags & IP6T_RT_SGS)
 170                         xtables_error(PARAMETER_PROBLEM,
 171                                    "Only one `--rt-segsleft' allowed");
 172                 xtables_check_inverse(optarg, &invert, &optind, 0);
 173                 parse_rt_segsleft(argv[optind-1], rtinfo->segsleft);
 174                 if (invert)
 175                         rtinfo->invflags |= IP6T_RT_INV_SGS;
 176                 rtinfo->flags |= IP6T_RT_SGS;
 177                 *flags |= IP6T_RT_SGS;
 178                 break;
 179         case '3':
 180                 if (*flags & IP6T_RT_LEN)
 181                         xtables_error(PARAMETER_PROBLEM,
 182                                    "Only one `--rt-len' allowed");
 183                 xtables_check_inverse(optarg, &invert, &optind, 0);
 184                 rtinfo->hdrlen = parse_rt_num(argv[optind-1], "length");
 185                 if (invert)
 186                         rtinfo->invflags |= IP6T_RT_INV_LEN;
 187                 rtinfo->flags |= IP6T_RT_LEN;
 188                 *flags |= IP6T_RT_LEN;
 189                 break;
 190         case '4':
 191                 if (*flags & IP6T_RT_RES)
 192                         xtables_error(PARAMETER_PROBLEM,
 193                                    "Only one `--rt-0-res' allowed");
 194                 if ( !(*flags & IP6T_RT_TYP) || (rtinfo->rt_type != 0) || (rtinfo->invflags & IP6T_RT_INV_TYP) )
 195                         xtables_error(PARAMETER_PROBLEM,
 196                                    "`--rt-type 0' required before `--rt-0-res'");
 197                 rtinfo->flags |= IP6T_RT_RES;
 198                 *flags |= IP6T_RT_RES;
 199                 break;
 200         case '5':
 201                 if (*flags & IP6T_RT_FST)
 202                         xtables_error(PARAMETER_PROBLEM,
 203                                    "Only one `--rt-0-addrs' allowed");
 204                 if ( !(*flags & IP6T_RT_TYP) || (rtinfo->rt_type != 0) || (rtinfo->invflags & IP6T_RT_INV_TYP) )
 205                         xtables_error(PARAMETER_PROBLEM,
 206                                    "`--rt-type 0' required before `--rt-0-addrs'");
 207                 xtables_check_inverse(optarg, &invert, &optind, 0);
 208                 if (invert)
 209                         xtables_error(PARAMETER_PROBLEM,
 210                                    " '!' not allowed with `--rt-0-addrs'");
 211                 rtinfo->addrnr = parse_addresses(argv[optind-1], rtinfo->addrs);
 212                 rtinfo->flags |= IP6T_RT_FST;
 213                 *flags |= IP6T_RT_FST;
 214                 break;
 215         case '6':
 216                 if (*flags & IP6T_RT_FST_NSTRICT)
 217                         xtables_error(PARAMETER_PROBLEM,
 218                                    "Only one `--rt-0-not-strict' allowed");
 219                 if ( !(*flags & IP6T_RT_FST) )
 220                         xtables_error(PARAMETER_PROBLEM,
 221                                    "`--rt-0-addr ...' required before `--rt-0-not-strict'");
 222                 rtinfo->flags |= IP6T_RT_FST_NSTRICT;
 223                 *flags |= IP6T_RT_FST_NSTRICT;
 224                 break;
 225         default:
 226                 return 0;
 227         }
 228
 229         return 1;
 230 }
 231
 232 static void
 233 print_nums(const char *name, u_int32_t min, u_int32_t max,
 234             int invert)
 235 {
 236         const char *inv = invert ? "!" : "";
 237
 238         if (min != 0 || max != 0xFFFFFFFF || invert) {
 239                 printf("%s", name);
 240                 if (min == max) {
 241                         printf(":%s", inv);
 242                         printf("%u", min);
 243                 } else {
 244                         printf("s:%s", inv);
 245                         printf("%u",min);
 246                         printf(":");
 247                         printf("%u",max);
 248                 }
 249                 printf(" ");
 250         }
 251 }
 252
 253 static void
 254 print_addresses(unsigned int addrnr, struct in6_addr *addrp)
 255 {
 256         unsigned int i;
 257
 258         for(i=0; i<addrnr; i++){
 259                 printf("%s%c", addr_to_numeric(&(addrp[i])), (i!=addrnr-1)?',':' ');
 260         }
 261 }
 262
 263 static void rt_print(const void *ip, const struct xt_entry_match *match,
 264                      int numeric)
 265 {
 266         const struct ip6t_rt *rtinfo = (struct ip6t_rt *)match->data;
 267
 268         printf("rt ");
 269         if (rtinfo->flags & IP6T_RT_TYP)
 270             printf("type:%s%d ", rtinfo->invflags & IP6T_RT_INV_TYP ? "!" : "",
 271                     rtinfo->rt_type);
 272         print_nums("segsleft", rtinfo->segsleft[0], rtinfo->segsleft[1],
 273                     rtinfo->invflags & IP6T_RT_INV_SGS);
 274         if (rtinfo->flags & IP6T_RT_LEN) {
 275                 printf("length");
 276                 printf(":%s", rtinfo->invflags & IP6T_RT_INV_LEN ? "!" : "");
 277                 printf("%u", rtinfo->hdrlen);
 278                 printf(" ");
 279         }
 280         if (rtinfo->flags & IP6T_RT_RES) printf("reserved ");
 281         if (rtinfo->flags & IP6T_RT_FST) printf("0-addrs ");
 282         print_addresses(rtinfo->addrnr, (struct in6_addr *)rtinfo->addrs);
 283         if (rtinfo->flags & IP6T_RT_FST_NSTRICT) printf("0-not-strict ");
 284         if (rtinfo->invflags & ~IP6T_RT_INV_MASK)
 285                 printf("Unknown invflags: 0x%X ",
 286                        rtinfo->invflags & ~IP6T_RT_INV_MASK);
 287 }
 288
 289 static void rt_save(const void *ip, const struct xt_entry_match *match)
 290 {
 291         const struct ip6t_rt *rtinfo = (struct ip6t_rt *)match->data;
 292
 293         if (rtinfo->flags & IP6T_RT_TYP) {
 294                 printf("%s--rt-type %u ",
 295                         (rtinfo->invflags & IP6T_RT_INV_TYP) ? "! " : "",
 296                         rtinfo->rt_type);
 297         }
 298
 299         if (!(rtinfo->segsleft[0] == 0
 300             && rtinfo->segsleft[1] == 0xFFFFFFFF)) {
 301                 printf("%s--rt-segsleft ",
 302                         (rtinfo->invflags & IP6T_RT_INV_SGS) ? "! " : "");
 303                 if (rtinfo->segsleft[0]
 304                     != rtinfo->segsleft[1])
 305                         printf("%u:%u ",
 306                                rtinfo->segsleft[0],
 307                                rtinfo->segsleft[1]);
 308                 else
 309                         printf("%u ",
 310                                rtinfo->segsleft[0]);
 311         }
 312
 313         if (rtinfo->flags & IP6T_RT_LEN) {
 314                 printf("%s--rt-len %u ",
 315                         (rtinfo->invflags & IP6T_RT_INV_LEN) ? "! " : "",
 316                         rtinfo->hdrlen);
 317         }
 318
 319         if (rtinfo->flags & IP6T_RT_RES) printf("--rt-0-res ");
 320         if (rtinfo->flags & IP6T_RT_FST) printf("--rt-0-addrs ");
 321         print_addresses(rtinfo->addrnr, (struct in6_addr *)rtinfo->addrs);
 322         if (rtinfo->flags & IP6T_RT_FST_NSTRICT) printf("--rt-0-not-strict ");
 323
 324 }
 325
 326 static struct xtables_match rt_mt6_reg = {
 327         .name           = "rt",
 328         .version        = XTABLES_VERSION,
 329         .family         = NFPROTO_IPV6,
 330         .size           = XT_ALIGN(sizeof(struct ip6t_rt)),
 331         .userspacesize  = XT_ALIGN(sizeof(struct ip6t_rt)),
 332         .help           = rt_help,
 333         .init           = rt_init,
 334         .parse          = rt_parse,
 335         .print          = rt_print,
 336         .save           = rt_save,
 337         .extra_opts     = rt_opts,
 338 };
 339
 340 void
 341 _init(void)
 342 {
 343         xtables_register_match(&rt_mt6_reg);
 344 }