extensions/libip6t_hbh.c

   1 /* Shared library add-on to ip6tables to add Hop-by-Hop 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_opts.h>
  11 #include <sys/types.h>
  12 #include <sys/socket.h>
  13 #include <arpa/inet.h>
  14
  15 #define DEBUG           0
  16
  17 static void hbh_help(void)
  18 {
  19         printf(
  20 "hbh match options:\n"
  21 "[!] --hbh-len length            total length of this header\n"
  22 "  --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
  23 "                                Options and its length (list, max: %d)\n",
  24 IP6T_OPTS_OPTSNR);
  25 }
  26
  27 static const struct option hbh_opts[] = {
  28         { "hbh-len", 1, NULL, '1' },
  29         { "hbh-opts", 1, NULL, '2' },
  30         { "hbh-not-strict", 1, NULL, '3' },
  31         { .name = NULL }
  32 };
  33
  34 static u_int32_t
  35 parse_opts_num(const char *idstr, const char *typestr)
  36 {
  37         unsigned long int id;
  38         char* ep;
  39
  40         id =  strtoul(idstr,&ep,0) ;
  41
  42         if ( idstr == ep ) {
  43                 xtables_error(PARAMETER_PROBLEM,
  44                            "hbh: no valid digits in %s `%s'", typestr, idstr);
  45         }
  46         if ( id == ULONG_MAX  && errno == ERANGE ) {
  47                 xtables_error(PARAMETER_PROBLEM,
  48                            "%s `%s' specified too big: would overflow",
  49                            typestr, idstr);
  50         }
  51         if ( *idstr != '\0'  && *ep != '\0' ) {
  52                 xtables_error(PARAMETER_PROBLEM,
  53                            "hbh: error parsing %s `%s'", typestr, idstr);
  54         }
  55         return id;
  56 }
  57
  58 static int
  59 parse_options(const char *optsstr, u_int16_t *opts)
  60 {
  61         char *buffer, *cp, *next, *range;
  62         unsigned int i;
  63
  64         buffer = strdup(optsstr);
  65         if (!buffer) xtables_error(OTHER_PROBLEM, "strdup failed");
  66
  67         for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
  68         {
  69                 next=strchr(cp, ',');
  70                 if (next) *next++='\0';
  71                 range = strchr(cp, ':');
  72                 if (range) {
  73                         if (i == IP6T_OPTS_OPTSNR-1)
  74                                 xtables_error(PARAMETER_PROBLEM,
  75                                            "too many ports specified");
  76                         *range++ = '\0';
  77                 }
  78                 opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
  79                 if (range) {
  80                         if (opts[i] == 0)
  81                                 xtables_error(PARAMETER_PROBLEM, "PAD0 has not got length");
  82                         opts[i] |= parse_opts_num(range, "length") & 0xFF;
  83                 } else {
  84                         opts[i] |= (0x00FF);
  85                 }
  86
  87 #if DEBUG
  88                 printf("opts str: %s %s\n", cp, range);
  89                 printf("opts opt: %04X\n", opts[i]);
  90 #endif
  91         }
  92         if (cp) xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
  93
  94         free(buffer);
  95
  96 #if DEBUG
  97         printf("addr nr: %d\n", i);
  98 #endif
  99
 100         return i;
 101 }
 102
 103 static void hbh_init(struct xt_entry_match *m)
 104 {
 105         struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
 106
 107         optinfo->hdrlen = 0;
 108         optinfo->flags = 0;
 109         optinfo->invflags = 0;
 110         optinfo->optsnr = 0;
 111 }
 112
 113 static int hbh_parse(int c, char **argv, int invert, unsigned int *flags,
 114                      const void *entry, struct xt_entry_match **match)
 115 {
 116         struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
 117
 118         switch (c) {
 119         case '1':
 120                 if (*flags & IP6T_OPTS_LEN)
 121                         xtables_error(PARAMETER_PROBLEM,
 122                                    "Only one `--hbh-len' allowed");
 123                 xtables_check_inverse(optarg, &invert, &optind, 0);
 124                 optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
 125                 if (invert)
 126                         optinfo->invflags |= IP6T_OPTS_INV_LEN;
 127                 optinfo->flags |= IP6T_OPTS_LEN;
 128                 *flags |= IP6T_OPTS_LEN;
 129                 break;
 130         case '2':
 131                 if (*flags & IP6T_OPTS_OPTS)
 132                         xtables_error(PARAMETER_PROBLEM,
 133                                    "Only one `--hbh-opts' allowed");
 134                 xtables_check_inverse(optarg, &invert, &optind, 0);
 135                 if (invert)
 136                         xtables_error(PARAMETER_PROBLEM,
 137                                 " '!' not allowed with `--hbh-opts'");
 138                 optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
 139                 optinfo->flags |= IP6T_OPTS_OPTS;
 140                 *flags |= IP6T_OPTS_OPTS;
 141                 break;
 142         case '3':
 143                 if (*flags & IP6T_OPTS_NSTRICT)
 144                         xtables_error(PARAMETER_PROBLEM,
 145                                    "Only one `--hbh-not-strict' allowed");
 146                 if ( !(*flags & IP6T_OPTS_OPTS) )
 147                         xtables_error(PARAMETER_PROBLEM,
 148                                    "`--hbh-opts ...' required before `--hbh-not-strict'");
 149                 optinfo->flags |= IP6T_OPTS_NSTRICT;
 150                 *flags |= IP6T_OPTS_NSTRICT;
 151                 break;
 152         default:
 153                 return 0;
 154         }
 155
 156         return 1;
 157 }
 158
 159 static void
 160 print_options(unsigned int optsnr, u_int16_t *optsp)
 161 {
 162         unsigned int i;
 163
 164         for(i=0; i<optsnr; i++){
 165                 printf("%d", (optsp[i] & 0xFF00)>>8);
 166                 if ((optsp[i] & 0x00FF) != 0x00FF){
 167                         printf(":%d", (optsp[i] & 0x00FF));
 168                 }
 169                 printf("%c", (i!=optsnr-1)?',':' ');
 170         }
 171 }
 172
 173 static void hbh_print(const void *ip, const struct xt_entry_match *match,
 174                       int numeric)
 175 {
 176         const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
 177
 178         printf("hbh ");
 179         if (optinfo->flags & IP6T_OPTS_LEN) {
 180                 printf("length");
 181                 printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
 182                 printf("%u", optinfo->hdrlen);
 183                 printf(" ");
 184         }
 185         if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
 186         print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
 187         if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
 188         if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
 189                 printf("Unknown invflags: 0x%X ",
 190                        optinfo->invflags & ~IP6T_OPTS_INV_MASK);
 191 }
 192
 193 static void hbh_save(const void *ip, const struct xt_entry_match *match)
 194 {
 195         const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
 196
 197         if (optinfo->flags & IP6T_OPTS_LEN) {
 198                 printf("%s--hbh-len %u ",
 199                         (optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
 200                         optinfo->hdrlen);
 201         }
 202
 203         if (optinfo->flags & IP6T_OPTS_OPTS)
 204                 printf("--hbh-opts ");
 205         print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
 206         if (optinfo->flags & IP6T_OPTS_NSTRICT)
 207                 printf("--hbh-not-strict ");
 208 }
 209
 210 static struct xtables_match hbh_mt6_reg = {
 211         .name           = "hbh",
 212         .version        = XTABLES_VERSION,
 213         .family         = NFPROTO_IPV6,
 214         .size           = XT_ALIGN(sizeof(struct ip6t_opts)),
 215         .userspacesize  = XT_ALIGN(sizeof(struct ip6t_opts)),
 216         .help           = hbh_help,
 217         .init           = hbh_init,
 218         .parse          = hbh_parse,
 219         .print          = hbh_print,
 220         .save           = hbh_save,
 221         .extra_opts     = hbh_opts,
 222 };
 223
 224 void
 225 _init(void)
 226 {
 227         xtables_register_match(&hbh_mt6_reg);
 228 }