extensions/libip6t_icmp6.c

   1 /* Shared library add-on to iptables to add ICMP support. */
   2 #include <stdio.h>
   3 #include <netdb.h>
   4 #include <string.h>
   5 #include <stdlib.h>
   6 #include <getopt.h>
   7 #include <ip6tables.h>
   8 #include <linux/netfilter_ipv6/ip6_tables.h>
   9
  10 struct icmpv6_names {
  11         const char *name;
  12         u_int8_t type;
  13         u_int8_t code_min, code_max;
  14 };
  15
  16 static const struct icmpv6_names icmpv6_codes[] = {
  17         { "destination-unreachable", 1, 0, 0xFF },
  18         {   "no-route", 1, 0, 0 },
  19         {   "communication-prohibited", 1, 1, 1 },
  20         {   "address-unreachable", 1, 3, 3 },
  21         {   "port-unreachable", 1, 4, 4 },
  22
  23         { "packet-too-big", 2, 0, 0xFF },
  24
  25         { "time-exceeded", 3, 0, 0xFF },
  26         /* Alias */ { "ttl-exceeded", 3, 0, 0xFF },
  27         {   "ttl-zero-during-transit", 3, 0, 0 },
  28         {   "ttl-zero-during-reassembly", 3, 1, 1 },
  29
  30         { "parameter-problem", 4, 0, 0xFF },
  31         {   "bad-header", 4, 0, 0 },
  32         {   "unknown-header-type", 4, 1, 1 },
  33         {   "unknown-option", 4, 2, 2 },
  34
  35         { "echo-request", 128, 0, 0xFF },
  36         /* Alias */ { "ping", 128, 0, 0xFF },
  37
  38         { "echo-reply", 129, 0, 0xFF },
  39         /* Alias */ { "pong", 129, 0, 0xFF },
  40
  41         { "router-solicitation", 133, 0, 0xFF },
  42
  43         { "router-advertisement", 134, 0, 0xFF },
  44
  45         { "neighbour-solicitation", 135, 0, 0xFF },
  46         /* Alias */ { "neighbor-solicitation", 135, 0, 0xFF },
  47
  48         { "neighbour-advertisement", 136, 0, 0xFF },
  49         /* Alias */ { "neighbor-advertisement", 136, 0, 0xFF },
  50
  51         { "redirect", 137, 0, 0xFF },
  52
  53 };
  54
  55 static void
  56 print_icmpv6types()
  57 {
  58         unsigned int i;
  59         printf("Valid ICMPv6 Types:");
  60
  61         for (i = 0; i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names); i++) {
  62                 if (i && icmpv6_codes[i].type == icmpv6_codes[i-1].type) {
  63                         if (icmpv6_codes[i].code_min == icmpv6_codes[i-1].code_min
  64                             && (icmpv6_codes[i].code_max
  65                                 == icmpv6_codes[i-1].code_max))
  66                                 printf(" (%s)", icmpv6_codes[i].name);
  67                         else
  68                                 printf("\n   %s", icmpv6_codes[i].name);
  69                 }
  70                 else
  71                         printf("\n%s", icmpv6_codes[i].name);
  72         }
  73         printf("\n");
  74 }
  75
  76 /* Function which prints out usage message. */
  77 static void
  78 help(void)
  79 {
  80         printf(
  81 "ICMPv6 v%s options:\n"
  82 " --icmpv6-type [!] typename    match icmpv6 type\n"
  83 "                               (or numeric type or type/code)\n"
  84 "\n", IPTABLES_VERSION);
  85         print_icmpv6types();
  86 }
  87
  88 static struct option opts[] = {
  89         { "icmpv6-type", 1, 0, '1' },
  90         {0}
  91 };
  92
  93 static void
  94 parse_icmpv6(const char *icmpv6type, u_int8_t *type, u_int8_t code[])
  95 {
  96         unsigned int limit = sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
  97         unsigned int match = limit;
  98         unsigned int i;
  99
 100         for (i = 0; i < limit; i++) {
 101                 if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type))
 102                     == 0) {
 103                         if (match != limit)
 104                                 exit_error(PARAMETER_PROBLEM,
 105                                            "Ambiguous ICMPv6 type `%s':"
 106                                            " `%s' or `%s'?",
 107                                            icmpv6type,
 108                                            icmpv6_codes[match].name,
 109                                            icmpv6_codes[i].name);
 110                         match = i;
 111                 }
 112         }
 113
 114         if (match != limit) {
 115                 *type = icmpv6_codes[match].type;
 116                 code[0] = icmpv6_codes[match].code_min;
 117                 code[1] = icmpv6_codes[match].code_max;
 118         } else {
 119                 char *slash;
 120                 char buffer[strlen(icmpv6type) + 1];
 121                 unsigned int number;
 122
 123                 strcpy(buffer, icmpv6type);
 124                 slash = strchr(buffer, '/');
 125
 126                 if (slash)
 127                         *slash = '\0';
 128
 129                 if (string_to_number(buffer, 0, 255, &number) == -1)
 130                         exit_error(PARAMETER_PROBLEM,
 131                                    "Invalid ICMPv6 type `%s'\n", buffer);
 132                 *type = number;
 133                 if (slash) {
 134                         if (string_to_number(slash+1, 0, 255, &number) == -1)
 135                                 exit_error(PARAMETER_PROBLEM,
 136                                            "Invalid ICMPv6 code `%s'\n",
 137                                            slash+1);
 138                         code[0] = code[1] = number;
 139                 } else {
 140                         code[0] = 0;
 141                         code[1] = 0xFF;
 142                 }
 143         }
 144 }
 145
 146 /* Initialize the match. */
 147 static void
 148 init(struct ip6t_entry_match *m, unsigned int *nfcache)
 149 {
 150         struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data;
 151
 152         icmpv6info->code[1] = 0xFF;
 153 }
 154
 155 /* Function which parses command options; returns true if it
 156    ate an option */
 157 static int
 158 parse(int c, char **argv, int invert, unsigned int *flags,
 159       const struct ip6t_entry *entry,
 160       unsigned int *nfcache,
 161       struct ip6t_entry_match **match)
 162 {
 163         struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)(*match)->data;
 164
 165         switch (c) {
 166         case '1':
 167                 if (*flags == 1)
 168                         exit_error(PARAMETER_PROBLEM,
 169                                    "icmpv6 match: only use --icmpv6-type once!");
 170                 check_inverse(optarg, &invert, &optind, 0);
 171                 parse_icmpv6(argv[optind-1], &icmpv6info->type,
 172                              icmpv6info->code);
 173                 if (invert)
 174                         icmpv6info->invflags |= IP6T_ICMP_INV;
 175                 *flags = 1;
 176                 break;
 177
 178         default:
 179                 return 0;
 180         }
 181
 182         return 1;
 183 }
 184
 185 static void print_icmpv6type(u_int8_t type,
 186                            u_int8_t code_min, u_int8_t code_max,
 187                            int invert,
 188                            int numeric)
 189 {
 190         if (!numeric) {
 191                 unsigned int i;
 192
 193                 for (i = 0;
 194                      i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names);
 195                      i++) {
 196                         if (icmpv6_codes[i].type == type
 197                             && icmpv6_codes[i].code_min == code_min
 198                             && icmpv6_codes[i].code_max == code_max)
 199                                 break;
 200                 }
 201
 202                 if (i != sizeof(icmpv6_codes)/sizeof(struct icmpv6_names)) {
 203                         printf("%s%s ",
 204                                invert ? "!" : "",
 205                                icmpv6_codes[i].name);
 206                         return;
 207                 }
 208         }
 209
 210         if (invert)
 211                 printf("!");
 212
 213         printf("type %u", type);
 214         if (code_min == 0 && code_max == 0xFF)
 215                 printf(" ");
 216         else if (code_min == code_max)
 217                 printf(" code %u ", code_min);
 218         else
 219                 printf(" codes %u-%u ", code_min, code_max);
 220 }
 221
 222 /* Prints out the union ipt_matchinfo. */
 223 static void
 224 print(const struct ip6t_ip6 *ip,
 225       const struct ip6t_entry_match *match,
 226       int numeric)
 227 {
 228         const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
 229
 230         printf("ipv6-icmp ");
 231         print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1],
 232                        icmpv6->invflags & IP6T_ICMP_INV,
 233                        numeric);
 234
 235         if (icmpv6->invflags & ~IP6T_ICMP_INV)
 236                 printf("Unknown invflags: 0x%X ",
 237                        icmpv6->invflags & ~IP6T_ICMP_INV);
 238 }
 239
 240 /* Saves the match in parsable form to stdout. */
 241 static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
 242 {
 243         const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data;
 244
 245         if (icmpv6->invflags & IP6T_ICMP_INV)
 246                 printf("! ");
 247
 248         printf("--icmpv6-type %u", icmpv6->type);
 249         if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF)
 250                 printf("/%u", icmpv6->code[0]);
 251         printf(" ");
 252 }
 253
 254 static void final_check(unsigned int flags)
 255 {
 256         if (!flags)
 257                 exit_error(PARAMETER_PROBLEM,
 258                            "icmpv6 match: You must specify `--icmpv6-type'");
 259 }
 260
 261 static struct ip6tables_match icmpv6 = {
 262         .name           = "icmp6",
 263         .version        = IPTABLES_VERSION,
 264         .size           = IP6T_ALIGN(sizeof(struct ip6t_icmp)),
 265         .userspacesize  = IP6T_ALIGN(sizeof(struct ip6t_icmp)),
 266         .help           = &help,
 267         .init           = &init,
 268         .parse          = &parse,
 269         .final_check    = &final_check,
 270         .print          = &print,
 271         .save           = &save,
 272         .extra_opts     = opts,
 273 };
 274
 275 void _init(void)
 276 {
 277         register_match6(&icmpv6);
 278 }