Unifies libip[6]t_state into libxt_state

1 files changed, 178 insertions, 0 deletions

diff --git a/extensions/libxt_state.c b/extensions/libxt_state.c
new file mode 100644
index 00000000..3972a3bb
--- /dev/null
+++ b/extensions/libxt_state.c
@@ -0,0 +1,178 @@
+/* Shared library add-on to iptables to add state tracking support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <xtables.h>
+#include <linux/netfilter/nf_conntrack_common.h>
+#include <linux/netfilter/xt_state.h>
+
+#ifndef XT_STATE_UNTRACKED
+#define XT_STATE_UNTRACKED (1 << (IP_CT_NUMBER + 1))
+#endif
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"state v%s options:\n"
+" [!] --state [INVALID|ESTABLISHED|NEW|RELATED|UNTRACKED][,...]\n"
+"				State(s) to match\n"
+"\n", IPTABLES_VERSION);
+}
+
+static const struct option opts[] = {
+	{ "state", 1, 0, '1' },
+	{0}
+};
+
+static int
+parse_state(const char *state, size_t strlen, struct xt_state_info *sinfo)
+{
+	if (strncasecmp(state, "INVALID", strlen) == 0)
+		sinfo->statemask |= XT_STATE_INVALID;
+	else if (strncasecmp(state, "NEW", strlen) == 0)
+		sinfo->statemask |= XT_STATE_BIT(IP_CT_NEW);
+	else if (strncasecmp(state, "ESTABLISHED", strlen) == 0)
+		sinfo->statemask |= XT_STATE_BIT(IP_CT_ESTABLISHED);
+	else if (strncasecmp(state, "RELATED", strlen) == 0)
+		sinfo->statemask |= XT_STATE_BIT(IP_CT_RELATED);
+	else if (strncasecmp(state, "UNTRACKED", strlen) == 0)
+		sinfo->statemask |= XT_STATE_UNTRACKED;
+	else
+		return 0;
+	return 1;
+}
+
+static void
+parse_states(const char *arg, struct xt_state_info *sinfo)
+{
+	const char *comma;
+
+	while ((comma = strchr(arg, ',')) != NULL) {
+		if (comma == arg || !parse_state(arg, comma-arg, sinfo))
+			exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
+		arg = comma+1;
+	}
+
+	if (strlen(arg) == 0 || !parse_state(arg, strlen(arg), sinfo))
+		exit_error(PARAMETER_PROBLEM, "Bad state `%s'", arg);
+}
+
+/* Function which parses command options; returns true if it
+   ate an option */
+static int
+parse(int c, char **argv, int invert, unsigned int *flags,
+      const void *entry,
+      unsigned int *nfcache,
+      struct xt_entry_match **match)
+{
+	struct xt_state_info *sinfo = (struct xt_state_info *)(*match)->data;
+
+	switch (c) {
+	case '1':
+		check_inverse(optarg, &invert, &optind, 0);
+
+		parse_states(argv[optind-1], sinfo);
+		if (invert)
+			sinfo->statemask = ~sinfo->statemask;
+		*flags = 1;
+		break;
+
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+/* Final check; must have specified --state. */
+static void final_check(unsigned int flags)
+{
+	if (!flags)
+		exit_error(PARAMETER_PROBLEM, "You must specify `--state'");
+}
+
+static void print_state(unsigned int statemask)
+{
+	const char *sep = "";
+
+	if (statemask & XT_STATE_INVALID) {
+		printf("%sINVALID", sep);
+		sep = ",";
+	}
+	if (statemask & XT_STATE_BIT(IP_CT_NEW)) {
+		printf("%sNEW", sep);
+		sep = ",";
+	}
+	if (statemask & XT_STATE_BIT(IP_CT_RELATED)) {
+		printf("%sRELATED", sep);
+		sep = ",";
+	}
+	if (statemask & XT_STATE_BIT(IP_CT_ESTABLISHED)) {
+		printf("%sESTABLISHED", sep);
+		sep = ",";
+	}
+	if (statemask & XT_STATE_UNTRACKED) {
+		printf("%sUNTRACKED", sep);
+		sep = ",";
+	}
+	printf(" ");
+}
+
+/* Prints out the matchinfo. */
+static void
+print(const void *ip,
+      const struct xt_entry_match *match,
+      int numeric)
+{
+	struct xt_state_info *sinfo = (struct xt_state_info *)match->data;
+
+	printf("state ");
+	print_state(sinfo->statemask);
+}
+
+/* Saves the matchinfo in parsable form to stdout. */
+static void save(const void *ip, const struct xt_entry_match *match)
+{
+	struct xt_state_info *sinfo = (struct xt_state_info *)match->data;
+
+	printf("--state ");
+	print_state(sinfo->statemask);
+}
+
+static struct xtables_match state = { 
+	.family		= AF_INET,
+	.name		= "state",
+	.version	= IPTABLES_VERSION,
+	.size		= XT_ALIGN(sizeof(struct xt_state_info)),
+	.userspacesize	= XT_ALIGN(sizeof(struct xt_state_info)),
+	.help		= &help,
+	.parse		= &parse,
+	.final_check	= &final_check,
+	.print		= &print,
+	.save		= &save,
+	.extra_opts	= opts,
+};
+
+static struct xtables_match state6 = { 
+	.family		= AF_INET6,
+	.name		= "state",
+	.version	= IPTABLES_VERSION,
+	.size		= XT_ALIGN(sizeof(struct xt_state_info)),
+	.userspacesize	= XT_ALIGN(sizeof(struct xt_state_info)),
+	.help		= &help,
+	.parse		= &parse,
+	.final_check	= &final_check,
+	.print		= &print,
+	.save		= &save,
+	.extra_opts	= opts,
+};
+
+void _init(void)
+{
+	xtables_register_match(&state);
+	xtables_register_match(&state6);
+}