+++ /dev/null
-/* Shared library add-on to iptables to add TCP support. */
-#include <stdio.h>
-#include <netdb.h>
-#include <string.h>
-#include <stdlib.h>
-#include <getopt.h>
-#include <xtables.h>
-#include <linux/netfilter/xt_tcpudp.h>
-
-/* Function which prints out usage message. */
-static void tcp_help(void)
-{
- printf(
-"tcp match options:\n"
-" --tcp-flags [!] mask comp match when TCP flags & mask == comp\n"
-" (Flags: SYN ACK FIN RST URG PSH ALL NONE)\n"
-"[!] --syn match when only SYN flag set\n"
-" (equivalent to --tcp-flags SYN,RST,ACK,FIN SYN)\n"
-" --source-port [!] port[:port]\n"
-" --sport ...\n"
-" match source port(s)\n"
-" --destination-port [!] port[:port]\n"
-" --dport ...\n"
-" match destination port(s)\n"
-" --tcp-option [!] number match if TCP option set\n");
-}
-
-static const struct option tcp_opts[] = {
- { "source-port", 1, NULL, '1' },
- { "sport", 1, NULL, '1' }, /* synonym */
- { "destination-port", 1, NULL, '2' },
- { "dport", 1, NULL, '2' }, /* synonym */
- { "syn", 0, NULL, '3' },
- { "tcp-flags", 1, NULL, '4' },
- { "tcp-option", 1, NULL, '5' },
- { .name = NULL }
-};
-
-static void
-parse_tcp_ports(const char *portstring, u_int16_t *ports)
-{
- char *buffer;
- char *cp;
-
- buffer = strdup(portstring);
- if ((cp = strchr(buffer, ':')) == NULL)
- ports[0] = ports[1] = parse_port(buffer, "tcp");
- else {
- *cp = '\0';
- cp++;
-
- ports[0] = buffer[0] ? parse_port(buffer, "tcp") : 0;
- ports[1] = cp[0] ? parse_port(cp, "tcp") : 0xFFFF;
-
- if (ports[0] > ports[1])
- exit_error(PARAMETER_PROBLEM,
- "invalid portrange (min > max)");
- }
- free(buffer);
-}
-
-struct tcp_flag_names {
- const char *name;
- unsigned int flag;
-};
-
-static const struct tcp_flag_names tcp_flag_names[]
-= { { "FIN", 0x01 },
- { "SYN", 0x02 },
- { "RST", 0x04 },
- { "PSH", 0x08 },
- { "ACK", 0x10 },
- { "URG", 0x20 },
- { "ALL", 0x3F },
- { "NONE", 0 },
-};
-
-static unsigned int
-parse_tcp_flag(const char *flags)
-{
- unsigned int ret = 0;
- char *ptr;
- char *buffer;
-
- buffer = strdup(flags);
-
- for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
- unsigned int i;
- for (i = 0;
- i < sizeof(tcp_flag_names)/sizeof(struct tcp_flag_names);
- i++) {
- if (strcasecmp(tcp_flag_names[i].name, ptr) == 0) {
- ret |= tcp_flag_names[i].flag;
- break;
- }
- }
- if (i == sizeof(tcp_flag_names)/sizeof(struct tcp_flag_names))
- exit_error(PARAMETER_PROBLEM,
- "Unknown TCP flag `%s'", ptr);
- }
-
- free(buffer);
- return ret;
-}
-
-static void
-parse_tcp_flags(struct xt_tcp *tcpinfo,
- const char *mask,
- const char *cmp,
- int invert)
-{
- tcpinfo->flg_mask = parse_tcp_flag(mask);
- tcpinfo->flg_cmp = parse_tcp_flag(cmp);
-
- if (invert)
- tcpinfo->invflags |= XT_TCP_INV_FLAGS;
-}
-
-static void
-parse_tcp_option(const char *option, u_int8_t *result)
-{
- unsigned int ret;
-
- if (string_to_number(option, 1, 255, &ret) == -1)
- exit_error(PARAMETER_PROBLEM, "Bad TCP option `%s'", option);
-
- *result = (u_int8_t)ret;
-}
-
-/* Initialize the match. */
-static void tcp_init(struct xt_entry_match *m)
-{
- struct xt_tcp *tcpinfo = (struct xt_tcp *)m->data;
-
- tcpinfo->spts[1] = tcpinfo->dpts[1] = 0xFFFF;
-}
-
-#define TCP_SRC_PORTS 0x01
-#define TCP_DST_PORTS 0x02
-#define TCP_FLAGS 0x04
-#define TCP_OPTION 0x08
-
-/* Function which parses command options; returns true if it
- ate an option. */
-static int
-tcp_parse(int c, char **argv, int invert, unsigned int *flags,
- const void *entry, struct xt_entry_match **match)
-{
- struct xt_tcp *tcpinfo = (struct xt_tcp *)(*match)->data;
-
- switch (c) {
- case '1':
- if (*flags & TCP_SRC_PORTS)
- exit_error(PARAMETER_PROBLEM,
- "Only one `--source-port' allowed");
- check_inverse(optarg, &invert, &optind, 0);
- parse_tcp_ports(argv[optind-1], tcpinfo->spts);
- if (invert)
- tcpinfo->invflags |= XT_TCP_INV_SRCPT;
- *flags |= TCP_SRC_PORTS;
- break;
-
- case '2':
- if (*flags & TCP_DST_PORTS)
- exit_error(PARAMETER_PROBLEM,
- "Only one `--destination-port' allowed");
- check_inverse(optarg, &invert, &optind, 0);
- parse_tcp_ports(argv[optind-1], tcpinfo->dpts);
- if (invert)
- tcpinfo->invflags |= XT_TCP_INV_DSTPT;
- *flags |= TCP_DST_PORTS;
- break;
-
- case '3':
- if (*flags & TCP_FLAGS)
- exit_error(PARAMETER_PROBLEM,
- "Only one of `--syn' or `--tcp-flags' "
- " allowed");
- parse_tcp_flags(tcpinfo, "SYN,RST,ACK,FIN", "SYN", invert);
- *flags |= TCP_FLAGS;
- break;
-
- case '4':
- if (*flags & TCP_FLAGS)
- exit_error(PARAMETER_PROBLEM,
- "Only one of `--syn' or `--tcp-flags' "
- " allowed");
- check_inverse(optarg, &invert, &optind, 0);
-
- if (!argv[optind]
- || argv[optind][0] == '-' || argv[optind][0] == '!')
- exit_error(PARAMETER_PROBLEM,
- "--tcp-flags requires two args.");
-
- parse_tcp_flags(tcpinfo, argv[optind-1], argv[optind],
- invert);
- optind++;
- *flags |= TCP_FLAGS;
- break;
-
- case '5':
- if (*flags & TCP_OPTION)
- exit_error(PARAMETER_PROBLEM,
- "Only one `--tcp-option' allowed");
- check_inverse(optarg, &invert, &optind, 0);
- parse_tcp_option(argv[optind-1], &tcpinfo->option);
- if (invert)
- tcpinfo->invflags |= XT_TCP_INV_OPTION;
- *flags |= TCP_OPTION;
- break;
-
- default:
- return 0;
- }
-
- return 1;
-}
-
-static char *
-port_to_service(int port)
-{
- struct servent *service;
-
- if ((service = getservbyport(htons(port), "tcp")))
- return service->s_name;
-
- return NULL;
-}
-
-static void
-print_port(u_int16_t port, int numeric)
-{
- char *service;
-
- if (numeric || (service = port_to_service(port)) == NULL)
- printf("%u", port);
- else
- printf("%s", service);
-}
-
-static void
-print_ports(const char *name, u_int16_t min, u_int16_t max,
- int invert, int numeric)
-{
- const char *inv = invert ? "!" : "";
-
- if (min != 0 || max != 0xFFFF || invert) {
- printf("%s", name);
- if (min == max) {
- printf(":%s", inv);
- print_port(min, numeric);
- } else {
- printf("s:%s", inv);
- print_port(min, numeric);
- printf(":");
- print_port(max, numeric);
- }
- printf(" ");
- }
-}
-
-static void
-print_option(u_int8_t option, int invert, int numeric)
-{
- if (option || invert)
- printf("option=%s%u ", invert ? "!" : "", option);
-}
-
-static void
-print_tcpf(u_int8_t flags)
-{
- int have_flag = 0;
-
- while (flags) {
- unsigned int i;
-
- for (i = 0; (flags & tcp_flag_names[i].flag) == 0; i++);
-
- if (have_flag)
- printf(",");
- printf("%s", tcp_flag_names[i].name);
- have_flag = 1;
-
- flags &= ~tcp_flag_names[i].flag;
- }
-
- if (!have_flag)
- printf("NONE");
-}
-
-static void
-print_flags(u_int8_t mask, u_int8_t cmp, int invert, int numeric)
-{
- if (mask || invert) {
- printf("flags:%s", invert ? "!" : "");
- if (numeric)
- printf("0x%02X/0x%02X ", mask, cmp);
- else {
- print_tcpf(mask);
- printf("/");
- print_tcpf(cmp);
- printf(" ");
- }
- }
-}
-
-/* Prints out the union ipt_matchinfo. */
-static void
-tcp_print(const void *ip, const struct xt_entry_match *match, int numeric)
-{
- const struct xt_tcp *tcp = (struct xt_tcp *)match->data;
-
- printf("tcp ");
- print_ports("spt", tcp->spts[0], tcp->spts[1],
- tcp->invflags & XT_TCP_INV_SRCPT,
- numeric);
- print_ports("dpt", tcp->dpts[0], tcp->dpts[1],
- tcp->invflags & XT_TCP_INV_DSTPT,
- numeric);
- print_option(tcp->option,
- tcp->invflags & XT_TCP_INV_OPTION,
- numeric);
- print_flags(tcp->flg_mask, tcp->flg_cmp,
- tcp->invflags & XT_TCP_INV_FLAGS,
- numeric);
- if (tcp->invflags & ~XT_TCP_INV_MASK)
- printf("Unknown invflags: 0x%X ",
- tcp->invflags & ~XT_TCP_INV_MASK);
-}
-
-/* Saves the union ipt_matchinfo in parsable form to stdout. */
-static void tcp_save(const void *ip, const struct xt_entry_match *match)
-{
- const struct xt_tcp *tcpinfo = (struct xt_tcp *)match->data;
-
- if (tcpinfo->spts[0] != 0
- || tcpinfo->spts[1] != 0xFFFF) {
- if (tcpinfo->invflags & XT_TCP_INV_SRCPT)
- printf("! ");
- if (tcpinfo->spts[0]
- != tcpinfo->spts[1])
- printf("--sport %u:%u ",
- tcpinfo->spts[0],
- tcpinfo->spts[1]);
- else
- printf("--sport %u ",
- tcpinfo->spts[0]);
- }
-
- if (tcpinfo->dpts[0] != 0
- || tcpinfo->dpts[1] != 0xFFFF) {
- if (tcpinfo->invflags & XT_TCP_INV_DSTPT)
- printf("! ");
- if (tcpinfo->dpts[0]
- != tcpinfo->dpts[1])
- printf("--dport %u:%u ",
- tcpinfo->dpts[0],
- tcpinfo->dpts[1]);
- else
- printf("--dport %u ",
- tcpinfo->dpts[0]);
- }
-
- if (tcpinfo->option
- || (tcpinfo->invflags & XT_TCP_INV_OPTION)) {
- if (tcpinfo->invflags & XT_TCP_INV_OPTION)
- printf("! ");
- printf("--tcp-option %u ", tcpinfo->option);
- }
-
- if (tcpinfo->flg_mask
- || (tcpinfo->invflags & XT_TCP_INV_FLAGS)) {
- if (tcpinfo->invflags & XT_TCP_INV_FLAGS)
- printf("! ");
- printf("--tcp-flags ");
- if (tcpinfo->flg_mask != 0xFF) {
- print_tcpf(tcpinfo->flg_mask);
- }
- printf(" ");
- print_tcpf(tcpinfo->flg_cmp);
- printf(" ");
- }
-}
-
-static struct xtables_match tcp_match = {
- .family = AF_INET,
- .name = "tcp",
- .version = XTABLES_VERSION,
- .size = XT_ALIGN(sizeof(struct xt_tcp)),
- .userspacesize = XT_ALIGN(sizeof(struct xt_tcp)),
- .help = tcp_help,
- .init = tcp_init,
- .parse = tcp_parse,
- .print = tcp_print,
- .save = tcp_save,
- .extra_opts = tcp_opts,
-};
-
-static struct xtables_match tcp_match6 = {
- .family = AF_INET6,
- .name = "tcp",
- .version = XTABLES_VERSION,
- .size = XT_ALIGN(sizeof(struct xt_tcp)),
- .userspacesize = XT_ALIGN(sizeof(struct xt_tcp)),
- .help = tcp_help,
- .init = tcp_init,
- .parse = tcp_parse,
- .print = tcp_print,
- .save = tcp_save,
- .extra_opts = tcp_opts,
-};
-
-void
-_init(void)
-{
- xtables_register_match(&tcp_match);
- xtables_register_match(&tcp_match6);
-}
git://git.onelab.eu / iptables.git / blobdiff