release/src/router/iptables/extensions/libip6t_hbh.c

   1 /* Shared library add-on to ip6tables to add Hop-by-Hop and Dst headers 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 <ip6tables.h>
   9 /*#include <linux/in6.h>*/
  10 #include <linux/netfilter_ipv6/ip6t_opts.h>
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #include <arpa/inet.h>
  14
  15 #define DEBUG           0
  16 #define HOPBYHOP        1
  17 #define UNAME           (HOPBYHOP ? "HBH" : "DST")
  18 #define LNAME           (HOPBYHOP ? "hbh" : "dst")
  19
  20 /* Function which prints out usage message. */
  21 static void
  22 help(void)
  23 {
  24         printf(
  25 "%s v%s options:\n"
  26 " --%s-len [!] length           total length of this header\n"
  27 " --%s-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
  28 "                               Options and its length (list, max: %d)\n",
  29 UNAME , IPTABLES_VERSION, LNAME, LNAME, IP6T_OPTS_OPTSNR);
  30 }
  31
  32 #if HOPBYHOP
  33 static struct option opts[] = {
  34         { "hbh-len", 1, 0, '1' },
  35         { "hbh-opts", 1, 0, '2' },
  36         { "hbh-not-strict", 1, 0, '3' },
  37         {0}
  38 };
  39 #else
  40 static struct option opts[] = {
  41         { "dst-len", 1, 0, '1' },
  42         { "dst-opts", 1, 0, '2' },
  43         { "dst-not-strict", 1, 0, '3' },
  44         {0}
  45 };
  46 #endif
  47
  48 static u_int32_t
  49 parse_opts_num(const char *idstr, const char *typestr)
  50 {
  51         unsigned long int id;
  52         char* ep;
  53
  54         id =  strtoul(idstr,&ep,0) ;
  55
  56         if ( idstr == ep ) {
  57                 exit_error(PARAMETER_PROBLEM,
  58                            "%s no valid digits in %s `%s'", UNAME, typestr, idstr);
  59         }
  60         if ( id == ULONG_MAX  && errno == ERANGE ) {
  61                 exit_error(PARAMETER_PROBLEM,
  62                            "%s `%s' specified too big: would overflow",
  63                            typestr, idstr);
  64         }
  65         if ( *idstr != '\0'  && *ep != '\0' ) {
  66                 exit_error(PARAMETER_PROBLEM,
  67                            "%s error parsing %s `%s'", UNAME, typestr, idstr);
  68         }
  69         return (u_int32_t) id;
  70 }
  71
  72 static int
  73 parse_options(const char *optsstr, u_int16_t *opts)
  74 {
  75         char *buffer, *cp, *next, *range;
  76         unsigned int i;
  77
  78         buffer = strdup(optsstr);
  79         if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
  80
  81         for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
  82         {
  83                 next=strchr(cp, ',');
  84                 if (next) *next++='\0';
  85                 range = strchr(cp, ':');
  86                 if (range) {
  87                         if (i == IP6T_OPTS_OPTSNR-1)
  88                                 exit_error(PARAMETER_PROBLEM,
  89                                            "too many ports specified");
  90                         *range++ = '\0';
  91                 }
  92                 opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8);
  93                 if (range) {
  94                         if (opts[i] == 0)
  95                                 exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
  96                         opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
  97                                         0x000000FF);
  98                 } else {
  99                         opts[i] |= (0x00FF);
 100                 }
 101
 102 #if DEBUG
 103                 printf("opts str: %s %s\n", cp, range);
 104                 printf("opts opt: %04X\n", opts[i]);
 105 #endif
 106         }
 107         if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
 108
 109         free(buffer);
 110
 111 #if DEBUG
 112         printf("addr nr: %d\n", i);
 113 #endif
 114
 115         return i;
 116 }
 117
 118 /* Initialize the match. */
 119 static void
 120 init(struct ip6t_entry_match *m, unsigned int *nfcache)
 121 {
 122         struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
 123
 124         optinfo->hdrlen = 0;
 125         optinfo->flags = 0;
 126         optinfo->invflags = 0;
 127         optinfo->optsnr = 0;
 128 }
 129
 130 /* Function which parses command options; returns true if it
 131    ate an option */
 132 static int
 133 parse(int c, char **argv, int invert, unsigned int *flags,
 134       const struct ip6t_entry *entry,
 135       unsigned int *nfcache,
 136       struct ip6t_entry_match **match)
 137 {
 138         struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
 139
 140         switch (c) {
 141         case '1':
 142                 if (*flags & IP6T_OPTS_LEN)
 143                         exit_error(PARAMETER_PROBLEM,
 144                                    "Only one `--%s-len' allowed", LNAME);
 145                 check_inverse(optarg, &invert, &optind, 0);
 146                 optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
 147                 if (invert)
 148                         optinfo->invflags |= IP6T_OPTS_INV_LEN;
 149                 optinfo->flags |= IP6T_OPTS_LEN;
 150                 *flags |= IP6T_OPTS_LEN;
 151                 break;
 152         case '2':
 153                 if (*flags & IP6T_OPTS_OPTS)
 154                         exit_error(PARAMETER_PROBLEM,
 155                                    "Only one `--%s-opts' allowed", LNAME);
 156                 check_inverse(optarg, &invert, &optind, 0);
 157                 if (invert)
 158                         exit_error(PARAMETER_PROBLEM,
 159                                 " '!' not allowed with `--%s-opts'", LNAME);
 160                 optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
 161                 optinfo->flags |= IP6T_OPTS_OPTS;
 162                 *flags |= IP6T_OPTS_OPTS;
 163                 break;
 164         case '3':
 165                 if (*flags & IP6T_OPTS_NSTRICT)
 166                         exit_error(PARAMETER_PROBLEM,
 167                                    "Only one `--%s-not-strict' allowed", LNAME);
 168                 if ( !(*flags & IP6T_OPTS_OPTS) )
 169                         exit_error(PARAMETER_PROBLEM,
 170                                    "`--%s-opts ...' required before `--%s-not-strict'", LNAME, LNAME);
 171                 optinfo->flags |= IP6T_OPTS_NSTRICT;
 172                 *flags |= IP6T_OPTS_NSTRICT;
 173                 break;
 174         default:
 175                 return 0;
 176         }
 177
 178         return 1;
 179 }
 180
 181 /* Final check; we don't care. */
 182 static void
 183 final_check(unsigned int flags)
 184 {
 185 }
 186
 187 static void
 188 print_options(int optsnr, u_int16_t *optsp)
 189 {
 190         unsigned int i;
 191
 192         for(i=0; i<optsnr; i++){
 193                 printf("%d", (optsp[i] & 0xFF00)>>8);
 194                 if ((optsp[i] & 0x00FF) != 0x00FF){
 195                         printf(":%d", (optsp[i] & 0x00FF));
 196                 }
 197                 printf("%c", (i!=optsnr-1)?',':' ');
 198         }
 199 }
 200
 201 /* Prints out the union ip6t_matchinfo. */
 202 static void
 203 print(const struct ip6t_ip6 *ip,
 204       const struct ip6t_entry_match *match, int numeric)
 205 {
 206         const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
 207
 208         printf("%s ", LNAME);
 209         if (optinfo->flags & IP6T_OPTS_LEN) {
 210                 printf("length");
 211                 printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
 212                 printf("%u", optinfo->hdrlen);
 213                 printf(" ");
 214         }
 215         if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
 216         print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
 217         if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
 218         if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
 219                 printf("Unknown invflags: 0x%X ",
 220                        optinfo->invflags & ~IP6T_OPTS_INV_MASK);
 221 }
 222
 223 /* Saves the union ip6t_matchinfo in parsable form to stdout. */
 224 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
 225 {
 226         const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
 227
 228         if (optinfo->flags & IP6T_OPTS_LEN) {
 229                 printf("--%s-len %s%u ", LNAME,
 230                         (optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
 231                         optinfo->hdrlen);
 232         }
 233
 234         if (optinfo->flags & IP6T_OPTS_OPTS) printf("--%s-opts ", LNAME);
 235         print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
 236         if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("--%s-not-strict ", LNAME);
 237
 238 }
 239
 240 static struct ip6tables_match optstruct = {
 241 #if HOPBYHOP
 242         .name           = "hbh",
 243 #else
 244         .name           = "dst",
 245 #endif
 246         .version        = IPTABLES_VERSION,
 247         .size           = IP6T_ALIGN(sizeof(struct ip6t_opts)),
 248         .userspacesize  = IP6T_ALIGN(sizeof(struct ip6t_opts)),
 249         .help           = &help,
 250         .init           = &init,
 251         .parse          = &parse,
 252         .final_check    = &final_check,
 253         .print          = &print,
 254         .save           = &save,
 255         .extra_opts     = opts,
 256 };
 257
 258 void
 259 _init(void)
 260 {
 261         register_match6(&optstruct);
 262 }