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-rwxr-xr-xextensions/.iplimit-test2
-rw-r--r--extensions/libipt_connlimit.c133
2 files changed, 135 insertions, 0 deletions
diff --git a/extensions/.iplimit-test b/extensions/.iplimit-test
new file mode 100755
index 0000000..dee32d9
--- /dev/null
+++ b/extensions/.iplimit-test
@@ -0,0 +1,2 @@
+#! /bin/sh
+[ -f $KERNEL_DIR/include/linux/netfilter_ipv4/ipt_iplimit.h ] && echo iplimit
diff --git a/extensions/libipt_connlimit.c b/extensions/libipt_connlimit.c
new file mode 100644
index 0000000..1600dea
--- /dev/null
+++ b/extensions/libipt_connlimit.c
@@ -0,0 +1,133 @@
+/* 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 <iptables.h>
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ipt_iplimit.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+ printf(
+"iplimit v%s options:\n"
+"[!] --iplimit-above n match if the number of existing tcp connections is (not) above n\n"
+" --iplimit-mask n group hosts using mask\n"
+"\n", NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+ { "iplimit-above", 1, 0, '1' },
+ { "iplimit-mask", 1, 0, '2' },
+ {0}
+};
+
+/* Initialize the match. */
+static void
+init(struct ipt_entry_match *m, unsigned int *nfcache)
+{
+ /* Can't cache this */
+ *nfcache |= NFC_UNKNOWN;
+}
+
+/* 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 struct ipt_entry *entry,
+ unsigned int *nfcache,
+ struct ipt_entry_match **match)
+{
+ struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)(*match)->data;
+
+ if (0 == (*flags & 2)) {
+ /* set default mask unless we've already seen a mask option */
+ info->mask = htonl(0xFFFFFFFF);
+ }
+
+ switch (c) {
+ case '1':
+ if (check_inverse(optarg, &invert))
+ optind++;
+ info->limit = atoi(argv[optind-1]);
+ info->inverse = invert;
+ *flags |= 1;
+ break;
+
+ case '2':
+ info->mask = htonl(0xFFFFFFFF << (32 - atoi(argv[optind-1])));
+ *flags |= 2;
+ break;
+
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Final check */
+static void final_check(unsigned int flags)
+{
+ if (!flags & 1)
+ exit_error(PARAMETER_PROBLEM, "You must specify `--iplimit-above'");
+}
+
+static int
+count_bits(u_int32_t mask)
+{
+ int i, bits;
+
+ for (bits = 0, i = 31; i >= 0; i--) {
+ if (mask & htonl((u_int32_t)1 << i)) {
+ bits++;
+ continue;
+ }
+ break;
+ }
+ return bits;
+}
+
+/* Prints out the matchinfo. */
+static void
+print(const struct ipt_ip *ip,
+ const struct ipt_entry_match *match,
+ int numeric)
+{
+ struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)match->data;
+
+ printf("#conn/%d %s %d", count_bits(info->mask),
+ info->inverse ? "<" : ">", info->limit);
+}
+
+/* Saves the matchinfo in parsable form to stdout. */
+static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
+{
+ struct ipt_iplimit_info *info = (struct ipt_iplimit_info*)match->data;
+
+ printf("%s--iplimit-above %d",info->inverse ? "! " : "",info->limit);
+ printf(" --iplimit-mask %d",count_bits(info->mask));
+}
+
+struct iptables_match iplimit
+= { NULL,
+ "iplimit",
+ NETFILTER_VERSION,
+ IPT_ALIGN(sizeof(struct ipt_iplimit_info)),
+ IPT_ALIGN(sizeof(struct ipt_iplimit_info)),
+ &help,
+ &init,
+ &parse,
+ &final_check,
+ &print,
+ &save,
+ opts
+};
+
+void _init(void)
+{
+ register_match(&iplimit);
+}