Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 1 | /* Shared library add-on to iptables to add TCP 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 | /* Function which prints out usage message. */ |
| 11 | static void |
| 12 | help(void) |
| 13 | { |
| 14 | printf( |
| 15 | "TCP v%s options:\n" |
| 16 | " --tcp-flags [!] mask comp match when TCP flags & mask == comp\n" |
| 17 | " (Flags: SYN ACK FIN RST URG PSH ALL NONE)\n" |
| 18 | "[!] --syn match when only SYN flag set\n" |
Patrick McHardyYasuyuki KOZAKAI | a8a4f5d | 2007-07-16 15:27:38 +0000 | [diff] [blame] | 19 | " (equivalent to --tcp-flags SYN,RST,ACK,FIN SYN)\n" |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 20 | " --source-port [!] port[:port]\n" |
| 21 | " --sport ...\n" |
| 22 | " match source port(s)\n" |
| 23 | " --destination-port [!] port[:port]\n" |
| 24 | " --dport ...\n" |
| 25 | " match destination port(s)\n" |
| 26 | " --tcp-option [!] number match if TCP option set\n\n", |
Harald Welte | 80fe35d | 2002-05-29 13:08:15 +0000 | [diff] [blame] | 27 | IPTABLES_VERSION); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 28 | } |
| 29 | |
| 30 | static struct option opts[] = { |
| 31 | { "source-port", 1, 0, '1' }, |
| 32 | { "sport", 1, 0, '1' }, /* synonym */ |
| 33 | { "destination-port", 1, 0, '2' }, |
| 34 | { "dport", 1, 0, '2' }, /* synonym */ |
| 35 | { "syn", 0, 0, '3' }, |
| 36 | { "tcp-flags", 1, 0, '4' }, |
| 37 | { "tcp-option", 1, 0, '5' }, |
| 38 | {0} |
| 39 | }; |
| 40 | |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 41 | static void |
| 42 | parse_tcp_ports(const char *portstring, u_int16_t *ports) |
| 43 | { |
| 44 | char *buffer; |
| 45 | char *cp; |
| 46 | |
| 47 | buffer = strdup(portstring); |
| 48 | if ((cp = strchr(buffer, ':')) == NULL) |
Phil Oester | dbac8ad | 2006-07-20 17:01:54 +0000 | [diff] [blame] | 49 | ports[0] = ports[1] = parse_port(buffer, "tcp"); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 50 | else { |
| 51 | *cp = '\0'; |
| 52 | cp++; |
| 53 | |
Phil Oester | dbac8ad | 2006-07-20 17:01:54 +0000 | [diff] [blame] | 54 | ports[0] = buffer[0] ? parse_port(buffer, "tcp") : 0; |
| 55 | ports[1] = cp[0] ? parse_port(cp, "tcp") : 0xFFFF; |
Harald Welte | d15fb34 | 2002-07-26 16:27:57 +0000 | [diff] [blame] | 56 | |
| 57 | if (ports[0] > ports[1]) |
| 58 | exit_error(PARAMETER_PROBLEM, |
| 59 | "invalid portrange (min > max)"); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 60 | } |
| 61 | free(buffer); |
| 62 | } |
| 63 | |
| 64 | struct tcp_flag_names { |
| 65 | const char *name; |
| 66 | unsigned int flag; |
| 67 | }; |
| 68 | |
| 69 | static struct tcp_flag_names tcp_flag_names[] |
| 70 | = { { "FIN", 0x01 }, |
| 71 | { "SYN", 0x02 }, |
| 72 | { "RST", 0x04 }, |
| 73 | { "PSH", 0x08 }, |
| 74 | { "ACK", 0x10 }, |
| 75 | { "URG", 0x20 }, |
| 76 | { "ALL", 0x3F }, |
| 77 | { "NONE", 0 }, |
| 78 | }; |
| 79 | |
| 80 | static unsigned int |
| 81 | parse_tcp_flag(const char *flags) |
| 82 | { |
| 83 | unsigned int ret = 0; |
| 84 | char *ptr; |
| 85 | char *buffer; |
| 86 | |
| 87 | buffer = strdup(flags); |
| 88 | |
| 89 | for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) { |
| 90 | unsigned int i; |
| 91 | for (i = 0; |
| 92 | i < sizeof(tcp_flag_names)/sizeof(struct tcp_flag_names); |
| 93 | i++) { |
| 94 | if (strcasecmp(tcp_flag_names[i].name, ptr) == 0) { |
| 95 | ret |= tcp_flag_names[i].flag; |
| 96 | break; |
| 97 | } |
| 98 | } |
| 99 | if (i == sizeof(tcp_flag_names)/sizeof(struct tcp_flag_names)) |
| 100 | exit_error(PARAMETER_PROBLEM, |
Harald Welte | 2aa78fe | 2003-03-30 18:29:56 +0000 | [diff] [blame] | 101 | "Unknown TCP flag `%s'", ptr); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 102 | } |
| 103 | |
| 104 | free(buffer); |
| 105 | return ret; |
| 106 | } |
| 107 | |
| 108 | static void |
| 109 | parse_tcp_flags(struct ip6t_tcp *tcpinfo, |
| 110 | const char *mask, |
| 111 | const char *cmp, |
| 112 | int invert) |
| 113 | { |
| 114 | tcpinfo->flg_mask = parse_tcp_flag(mask); |
| 115 | tcpinfo->flg_cmp = parse_tcp_flag(cmp); |
| 116 | |
| 117 | if (invert) |
| 118 | tcpinfo->invflags |= IP6T_TCP_INV_FLAGS; |
| 119 | } |
| 120 | |
| 121 | static void |
| 122 | parse_tcp_option(const char *option, u_int8_t *result) |
| 123 | { |
Harald Welte | b471976 | 2001-07-23 02:14:22 +0000 | [diff] [blame] | 124 | unsigned int ret; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 125 | |
András Kis-Szabó | b7ff0ae | 2002-07-08 10:58:50 +0000 | [diff] [blame] | 126 | if (string_to_number(option, 1, 255, &ret) == -1) |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 127 | exit_error(PARAMETER_PROBLEM, "Bad TCP option `%s'", option); |
| 128 | |
| 129 | *result = (u_int8_t)ret; |
| 130 | } |
| 131 | |
| 132 | /* Initialize the match. */ |
| 133 | static void |
| 134 | init(struct ip6t_entry_match *m, unsigned int *nfcache) |
| 135 | { |
| 136 | struct ip6t_tcp *tcpinfo = (struct ip6t_tcp *)m->data; |
| 137 | |
| 138 | tcpinfo->spts[1] = tcpinfo->dpts[1] = 0xFFFF; |
| 139 | } |
| 140 | |
| 141 | #define TCP_SRC_PORTS 0x01 |
| 142 | #define TCP_DST_PORTS 0x02 |
| 143 | #define TCP_FLAGS 0x04 |
| 144 | #define TCP_OPTION 0x08 |
| 145 | |
| 146 | /* Function which parses command options; returns true if it |
| 147 | ate an option. */ |
| 148 | static int |
| 149 | parse(int c, char **argv, int invert, unsigned int *flags, |
| 150 | const struct ip6t_entry *entry, |
| 151 | unsigned int *nfcache, |
| 152 | struct ip6t_entry_match **match) |
| 153 | { |
| 154 | struct ip6t_tcp *tcpinfo = (struct ip6t_tcp *)(*match)->data; |
| 155 | |
| 156 | switch (c) { |
| 157 | case '1': |
| 158 | if (*flags & TCP_SRC_PORTS) |
| 159 | exit_error(PARAMETER_PROBLEM, |
| 160 | "Only one `--source-port' allowed"); |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 161 | check_inverse(optarg, &invert, &optind, 0); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 162 | parse_tcp_ports(argv[optind-1], tcpinfo->spts); |
| 163 | if (invert) |
| 164 | tcpinfo->invflags |= IP6T_TCP_INV_SRCPT; |
| 165 | *flags |= TCP_SRC_PORTS; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 166 | break; |
| 167 | |
| 168 | case '2': |
| 169 | if (*flags & TCP_DST_PORTS) |
| 170 | exit_error(PARAMETER_PROBLEM, |
| 171 | "Only one `--destination-port' allowed"); |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 172 | check_inverse(optarg, &invert, &optind, 0); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 173 | parse_tcp_ports(argv[optind-1], tcpinfo->dpts); |
| 174 | if (invert) |
| 175 | tcpinfo->invflags |= IP6T_TCP_INV_DSTPT; |
| 176 | *flags |= TCP_DST_PORTS; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 177 | break; |
| 178 | |
| 179 | case '3': |
| 180 | if (*flags & TCP_FLAGS) |
| 181 | exit_error(PARAMETER_PROBLEM, |
| 182 | "Only one of `--syn' or `--tcp-flags' " |
| 183 | " allowed"); |
Yasuyuki KOZAKAI | a70d29f | 2007-07-16 10:07:30 +0000 | [diff] [blame] | 184 | parse_tcp_flags(tcpinfo, "SYN,RST,ACK,FIN", "SYN", invert); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 185 | *flags |= TCP_FLAGS; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 186 | break; |
| 187 | |
| 188 | case '4': |
| 189 | if (*flags & TCP_FLAGS) |
| 190 | exit_error(PARAMETER_PROBLEM, |
| 191 | "Only one of `--syn' or `--tcp-flags' " |
| 192 | " allowed"); |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 193 | check_inverse(optarg, &invert, &optind, 0); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 194 | |
| 195 | if (!argv[optind] |
| 196 | || argv[optind][0] == '-' || argv[optind][0] == '!') |
| 197 | exit_error(PARAMETER_PROBLEM, |
| 198 | "--tcp-flags requires two args."); |
| 199 | |
Harald Welte | d46818e | 2002-03-18 20:32:06 +0000 | [diff] [blame] | 200 | parse_tcp_flags(tcpinfo, argv[optind-1], argv[optind], |
| 201 | invert); |
| 202 | optind++; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 203 | *flags |= TCP_FLAGS; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 204 | break; |
| 205 | |
| 206 | case '5': |
| 207 | if (*flags & TCP_OPTION) |
| 208 | exit_error(PARAMETER_PROBLEM, |
| 209 | "Only one `--tcp-option' allowed"); |
Harald Welte | b77f1da | 2002-03-14 11:35:58 +0000 | [diff] [blame] | 210 | check_inverse(optarg, &invert, &optind, 0); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 211 | parse_tcp_option(argv[optind-1], &tcpinfo->option); |
| 212 | if (invert) |
| 213 | tcpinfo->invflags |= IP6T_TCP_INV_OPTION; |
| 214 | *flags |= TCP_OPTION; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 215 | break; |
| 216 | |
| 217 | default: |
| 218 | return 0; |
| 219 | } |
| 220 | |
| 221 | return 1; |
| 222 | } |
| 223 | |
| 224 | /* Final check; we don't care. */ |
| 225 | static void |
| 226 | final_check(unsigned int flags) |
| 227 | { |
| 228 | } |
| 229 | |
| 230 | static char * |
| 231 | port_to_service(int port) |
| 232 | { |
| 233 | struct servent *service; |
| 234 | |
| 235 | if ((service = getservbyport(htons(port), "tcp"))) |
| 236 | return service->s_name; |
| 237 | |
| 238 | return NULL; |
| 239 | } |
| 240 | |
| 241 | static void |
| 242 | print_port(u_int16_t port, int numeric) |
| 243 | { |
| 244 | char *service; |
| 245 | |
| 246 | if (numeric || (service = port_to_service(port)) == NULL) |
| 247 | printf("%u", port); |
| 248 | else |
| 249 | printf("%s", service); |
| 250 | } |
| 251 | |
| 252 | static void |
| 253 | print_ports(const char *name, u_int16_t min, u_int16_t max, |
| 254 | int invert, int numeric) |
| 255 | { |
| 256 | const char *inv = invert ? "!" : ""; |
| 257 | |
| 258 | if (min != 0 || max != 0xFFFF || invert) { |
| 259 | printf("%s", name); |
| 260 | if (min == max) { |
| 261 | printf(":%s", inv); |
| 262 | print_port(min, numeric); |
| 263 | } else { |
| 264 | printf("s:%s", inv); |
| 265 | print_port(min, numeric); |
| 266 | printf(":"); |
| 267 | print_port(max, numeric); |
| 268 | } |
| 269 | printf(" "); |
| 270 | } |
| 271 | } |
| 272 | |
| 273 | static void |
| 274 | print_option(u_int8_t option, int invert, int numeric) |
| 275 | { |
| 276 | if (option || invert) |
| 277 | printf("option=%s%u ", invert ? "!" : "", option); |
| 278 | } |
| 279 | |
| 280 | static void |
| 281 | print_tcpf(u_int8_t flags) |
| 282 | { |
| 283 | int have_flag = 0; |
| 284 | |
| 285 | while (flags) { |
| 286 | unsigned int i; |
| 287 | |
| 288 | for (i = 0; (flags & tcp_flag_names[i].flag) == 0; i++); |
| 289 | |
| 290 | if (have_flag) |
| 291 | printf(","); |
| 292 | printf("%s", tcp_flag_names[i].name); |
| 293 | have_flag = 1; |
| 294 | |
| 295 | flags &= ~tcp_flag_names[i].flag; |
| 296 | } |
| 297 | |
| 298 | if (!have_flag) |
| 299 | printf("NONE"); |
| 300 | } |
| 301 | |
| 302 | static void |
| 303 | print_flags(u_int8_t mask, u_int8_t cmp, int invert, int numeric) |
| 304 | { |
| 305 | if (mask || invert) { |
| 306 | printf("flags:%s", invert ? "!" : ""); |
| 307 | if (numeric) |
Harald Welte | 0b4efea | 2001-04-12 15:50:49 +0000 | [diff] [blame] | 308 | printf("0x%02X/0x%02X ", mask, cmp); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 309 | else { |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 310 | print_tcpf(mask); |
Harald Welte | d46818e | 2002-03-18 20:32:06 +0000 | [diff] [blame] | 311 | printf("/"); |
| 312 | print_tcpf(cmp); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 313 | printf(" "); |
| 314 | } |
| 315 | } |
| 316 | } |
| 317 | |
| 318 | /* Prints out the union ipt_matchinfo. */ |
| 319 | static void |
| 320 | print(const struct ip6t_ip6 *ip, |
| 321 | const struct ip6t_entry_match *match, int numeric) |
| 322 | { |
| 323 | const struct ip6t_tcp *tcp = (struct ip6t_tcp *)match->data; |
| 324 | |
| 325 | printf("tcp "); |
| 326 | print_ports("spt", tcp->spts[0], tcp->spts[1], |
| 327 | tcp->invflags & IP6T_TCP_INV_SRCPT, |
| 328 | numeric); |
| 329 | print_ports("dpt", tcp->dpts[0], tcp->dpts[1], |
| 330 | tcp->invflags & IP6T_TCP_INV_DSTPT, |
| 331 | numeric); |
| 332 | print_option(tcp->option, |
| 333 | tcp->invflags & IP6T_TCP_INV_OPTION, |
| 334 | numeric); |
| 335 | print_flags(tcp->flg_mask, tcp->flg_cmp, |
| 336 | tcp->invflags & IP6T_TCP_INV_FLAGS, |
| 337 | numeric); |
| 338 | if (tcp->invflags & ~IP6T_TCP_INV_MASK) |
| 339 | printf("Unknown invflags: 0x%X ", |
| 340 | tcp->invflags & ~IP6T_TCP_INV_MASK); |
| 341 | } |
| 342 | |
| 343 | /* Saves the union ipt_matchinfo in parsable form to stdout. */ |
| 344 | static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match) |
| 345 | { |
| 346 | const struct ip6t_tcp *tcpinfo = (struct ip6t_tcp *)match->data; |
| 347 | |
| 348 | if (tcpinfo->spts[0] != 0 |
András Kis-Szabó | b7ff0ae | 2002-07-08 10:58:50 +0000 | [diff] [blame] | 349 | || tcpinfo->spts[1] != 0xFFFF) { |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 350 | if (tcpinfo->invflags & IP6T_TCP_INV_SRCPT) |
| 351 | printf("! "); |
| 352 | if (tcpinfo->spts[0] |
| 353 | != tcpinfo->spts[1]) |
| 354 | printf("--sport %u:%u ", |
| 355 | tcpinfo->spts[0], |
| 356 | tcpinfo->spts[1]); |
| 357 | else |
| 358 | printf("--sport %u ", |
| 359 | tcpinfo->spts[0]); |
| 360 | } |
| 361 | |
| 362 | if (tcpinfo->dpts[0] != 0 |
Harald Welte | d46818e | 2002-03-18 20:32:06 +0000 | [diff] [blame] | 363 | || tcpinfo->dpts[1] != 0xFFFF) { |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 364 | if (tcpinfo->invflags & IP6T_TCP_INV_DSTPT) |
| 365 | printf("! "); |
| 366 | if (tcpinfo->dpts[0] |
| 367 | != tcpinfo->dpts[1]) |
| 368 | printf("--dport %u:%u ", |
| 369 | tcpinfo->dpts[0], |
| 370 | tcpinfo->dpts[1]); |
| 371 | else |
| 372 | printf("--dport %u ", |
| 373 | tcpinfo->dpts[0]); |
| 374 | } |
| 375 | |
| 376 | if (tcpinfo->option |
| 377 | || (tcpinfo->invflags & IP6T_TCP_INV_OPTION)) { |
| 378 | if (tcpinfo->invflags & IP6T_TCP_INV_OPTION) |
| 379 | printf("! "); |
| 380 | printf("--tcp-option %u ", tcpinfo->option); |
| 381 | } |
| 382 | |
| 383 | if (tcpinfo->flg_mask |
| 384 | || (tcpinfo->invflags & IP6T_TCP_INV_FLAGS)) { |
| 385 | if (tcpinfo->invflags & IP6T_TCP_INV_FLAGS) |
| 386 | printf("! "); |
| 387 | |
Harald Welte | d46818e | 2002-03-18 20:32:06 +0000 | [diff] [blame] | 388 | printf("--tcp-flags "); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 389 | if (tcpinfo->flg_mask != 0xFF) { |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 390 | print_tcpf(tcpinfo->flg_mask); |
| 391 | } |
Harald Welte | d46818e | 2002-03-18 20:32:06 +0000 | [diff] [blame] | 392 | printf(" "); |
| 393 | print_tcpf(tcpinfo->flg_cmp); |
| 394 | printf(" "); |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 395 | } |
| 396 | } |
| 397 | |
Harald Welte | 02aa733 | 2005-02-01 15:38:20 +0000 | [diff] [blame] | 398 | static struct ip6tables_match tcp = { |
| 399 | .name = "tcp", |
| 400 | .version = IPTABLES_VERSION, |
| 401 | .size = IP6T_ALIGN(sizeof(struct ip6t_tcp)), |
| 402 | .userspacesize = IP6T_ALIGN(sizeof(struct ip6t_tcp)), |
| 403 | .help = &help, |
| 404 | .init = &init, |
| 405 | .parse = &parse, |
Harald Welte | 58e7285 | 2005-02-01 15:42:08 +0000 | [diff] [blame] | 406 | .final_check = &final_check, |
Harald Welte | 02aa733 | 2005-02-01 15:38:20 +0000 | [diff] [blame] | 407 | .print = &print, |
| 408 | .save = &save, |
| 409 | .extra_opts = opts, |
| 410 | }; |
Philip Blundell | b47050c | 2000-06-04 17:38:47 +0000 | [diff] [blame] | 411 | |
| 412 | void |
| 413 | _init(void) |
| 414 | { |
| 415 | register_match6(&tcp); |
| 416 | } |