libip6t_icmp6.c revision 8b7c64d6ba156a99008fcd810cba874c73294333
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 10struct icmpv6_names { 11 const char *name; 12 u_int8_t type; 13 u_int8_t code_min, code_max; 14}; 15 16static 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 55static void 56print_icmpv6types(void) 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. */ 77static void icmp6_help(void) 78{ 79 printf( 80"icmpv6 match options:\n" 81" --icmpv6-type [!] typename match icmpv6 type\n" 82" (or numeric type or type/code)\n"); 83 print_icmpv6types(); 84} 85 86static const struct option icmp6_opts[] = { 87 { "icmpv6-type", 1, NULL, '1' }, 88 { .name = NULL } 89}; 90 91static void 92parse_icmpv6(const char *icmpv6type, u_int8_t *type, u_int8_t code[]) 93{ 94 unsigned int limit = sizeof(icmpv6_codes)/sizeof(struct icmpv6_names); 95 unsigned int match = limit; 96 unsigned int i; 97 98 for (i = 0; i < limit; i++) { 99 if (strncasecmp(icmpv6_codes[i].name, icmpv6type, strlen(icmpv6type)) 100 == 0) { 101 if (match != limit) 102 exit_error(PARAMETER_PROBLEM, 103 "Ambiguous ICMPv6 type `%s':" 104 " `%s' or `%s'?", 105 icmpv6type, 106 icmpv6_codes[match].name, 107 icmpv6_codes[i].name); 108 match = i; 109 } 110 } 111 112 if (match != limit) { 113 *type = icmpv6_codes[match].type; 114 code[0] = icmpv6_codes[match].code_min; 115 code[1] = icmpv6_codes[match].code_max; 116 } else { 117 char *slash; 118 char buffer[strlen(icmpv6type) + 1]; 119 unsigned int number; 120 121 strcpy(buffer, icmpv6type); 122 slash = strchr(buffer, '/'); 123 124 if (slash) 125 *slash = '\0'; 126 127 if (string_to_number(buffer, 0, 255, &number) == -1) 128 exit_error(PARAMETER_PROBLEM, 129 "Invalid ICMPv6 type `%s'\n", buffer); 130 *type = number; 131 if (slash) { 132 if (string_to_number(slash+1, 0, 255, &number) == -1) 133 exit_error(PARAMETER_PROBLEM, 134 "Invalid ICMPv6 code `%s'\n", 135 slash+1); 136 code[0] = code[1] = number; 137 } else { 138 code[0] = 0; 139 code[1] = 0xFF; 140 } 141 } 142} 143 144/* Initialize the match. */ 145static void icmp6_init(struct xt_entry_match *m) 146{ 147 struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)m->data; 148 149 icmpv6info->code[1] = 0xFF; 150} 151 152/* Function which parses command options; returns true if it 153 ate an option */ 154static int icmp6_parse(int c, char **argv, int invert, unsigned int *flags, 155 const void *entry, struct xt_entry_match **match) 156{ 157 struct ip6t_icmp *icmpv6info = (struct ip6t_icmp *)(*match)->data; 158 159 switch (c) { 160 case '1': 161 if (*flags == 1) 162 exit_error(PARAMETER_PROBLEM, 163 "icmpv6 match: only use --icmpv6-type once!"); 164 check_inverse(optarg, &invert, &optind, 0); 165 parse_icmpv6(argv[optind-1], &icmpv6info->type, 166 icmpv6info->code); 167 if (invert) 168 icmpv6info->invflags |= IP6T_ICMP_INV; 169 *flags = 1; 170 break; 171 172 default: 173 return 0; 174 } 175 176 return 1; 177} 178 179static void print_icmpv6type(u_int8_t type, 180 u_int8_t code_min, u_int8_t code_max, 181 int invert, 182 int numeric) 183{ 184 if (!numeric) { 185 unsigned int i; 186 187 for (i = 0; 188 i < sizeof(icmpv6_codes)/sizeof(struct icmpv6_names); 189 i++) { 190 if (icmpv6_codes[i].type == type 191 && icmpv6_codes[i].code_min == code_min 192 && icmpv6_codes[i].code_max == code_max) 193 break; 194 } 195 196 if (i != sizeof(icmpv6_codes)/sizeof(struct icmpv6_names)) { 197 printf("%s%s ", 198 invert ? "!" : "", 199 icmpv6_codes[i].name); 200 return; 201 } 202 } 203 204 if (invert) 205 printf("!"); 206 207 printf("type %u", type); 208 if (code_min == 0 && code_max == 0xFF) 209 printf(" "); 210 else if (code_min == code_max) 211 printf(" code %u ", code_min); 212 else 213 printf(" codes %u-%u ", code_min, code_max); 214} 215 216/* Prints out the union ipt_matchinfo. */ 217static void icmp6_print(const void *ip, const struct xt_entry_match *match, 218 int numeric) 219{ 220 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data; 221 222 printf("ipv6-icmp "); 223 print_icmpv6type(icmpv6->type, icmpv6->code[0], icmpv6->code[1], 224 icmpv6->invflags & IP6T_ICMP_INV, 225 numeric); 226 227 if (icmpv6->invflags & ~IP6T_ICMP_INV) 228 printf("Unknown invflags: 0x%X ", 229 icmpv6->invflags & ~IP6T_ICMP_INV); 230} 231 232/* Saves the match in parsable form to stdout. */ 233static void icmp6_save(const void *ip, const struct xt_entry_match *match) 234{ 235 const struct ip6t_icmp *icmpv6 = (struct ip6t_icmp *)match->data; 236 237 if (icmpv6->invflags & IP6T_ICMP_INV) 238 printf("! "); 239 240 printf("--icmpv6-type %u", icmpv6->type); 241 if (icmpv6->code[0] != 0 || icmpv6->code[1] != 0xFF) 242 printf("/%u", icmpv6->code[0]); 243 printf(" "); 244} 245 246static void icmp6_check(unsigned int flags) 247{ 248 if (!flags) 249 exit_error(PARAMETER_PROBLEM, 250 "icmpv6 match: You must specify `--icmpv6-type'"); 251} 252 253static struct xtables_match icmp6_mt6_reg = { 254 .name = "icmp6", 255 .version = XTABLES_VERSION, 256 .family = PF_INET6, 257 .size = XT_ALIGN(sizeof(struct ip6t_icmp)), 258 .userspacesize = XT_ALIGN(sizeof(struct ip6t_icmp)), 259 .help = icmp6_help, 260 .init = icmp6_init, 261 .parse = icmp6_parse, 262 .final_check = icmp6_check, 263 .print = icmp6_print, 264 .save = icmp6_save, 265 .extra_opts = icmp6_opts, 266}; 267 268void _init(void) 269{ 270 xtables_register_match(&icmp6_mt6_reg); 271} 272