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-rw-r--r--extensions/libip6t_hl.c177
1 files changed, 177 insertions, 0 deletions
diff --git a/extensions/libip6t_hl.c b/extensions/libip6t_hl.c
new file mode 100644
index 00000000..36f93317
--- /dev/null
+++ b/extensions/libip6t_hl.c
@@ -0,0 +1,177 @@
+/*
+ * IPv6 Hop Limit matching module
+ * Maciej Soltysiak <solt@dns.toxicfilms.tv>
+ * Based on HW's ttl match
+ * This program is released under the terms of GNU GPL
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <getopt.h>
+#include <ip6tables.h>
+
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_ipv6/ip6t_hl.h>
+
+static void help(void)
+{
+ printf(
+"HL match v%s options:\n"
+" --hl-eq value Match hop limit value\n"
+" --hl-lt value Match HL < value\n"
+" --hl-gt value Match HL > value\n"
+, IPTABLES_VERSION);
+}
+
+static void init(struct ip6t_entry_match *m, unsigned int *nfcache)
+{
+ /* caching not yet implemented */
+ *nfcache |= NFC_UNKNOWN;
+}
+
+static int parse(int c, char **argv, int invert, unsigned int *flags,
+ const struct ip6t_entry *entry, unsigned int *nfcache,
+ struct ip6t_entry_match **match)
+{
+ struct ip6t_hl_info *info = (struct ip6t_hl_info *) (*match)->data;
+ u_int8_t value;
+
+ check_inverse(optarg, &invert, &optind, 0);
+ value = atoi(argv[optind-1]);
+
+ if (*flags)
+ exit_error(PARAMETER_PROBLEM,
+ "Can't specify HL option twice");
+
+ if (!optarg)
+ exit_error(PARAMETER_PROBLEM,
+ "hl: You must specify a value");
+ switch (c) {
+ case '2':
+ if (invert)
+ info->mode = IP6T_HL_NE;
+ else
+ info->mode = IP6T_HL_EQ;
+
+ /* is 0 allowed? */
+ info->hop_limit = value;
+ *flags = 1;
+
+ break;
+ case '3':
+ if (invert)
+ exit_error(PARAMETER_PROBLEM,
+ "hl: unexpected `!'");
+
+ info->mode = IP6T_HL_LT;
+ info->hop_limit = value;
+ *flags = 1;
+
+ break;
+ case '4':
+ if (invert)
+ exit_error(PARAMETER_PROBLEM,
+ "hl: unexpected `!'");
+
+ info->mode = IP6T_HL_GT;
+ info->hop_limit = value;
+ *flags = 1;
+
+ break;
+ default:
+ return 0;
+
+ }
+
+ return 1;
+}
+
+static void final_check(unsigned int flags)
+{
+ if (!flags)
+ exit_error(PARAMETER_PROBLEM,
+ "HL match: You must specify one of "
+ "`--hl-eq', `--hl-lt', `--hl-gt");
+}
+
+static void print(const struct ip6t_ip6 *ip,
+ const struct ip6t_entry_match *match,
+ int numeric)
+{
+ const struct ip6t_hl_info *info =
+ (struct ip6t_hl_info *) match->data;
+
+ printf("HL match ");
+ switch (info->mode) {
+ case IP6T_HL_EQ:
+ printf("HL == ");
+ break;
+ case IP6T_HL_NE:
+ printf("HL != ");
+ break;
+ case IP6T_HL_LT:
+ printf("HL < ");
+ break;
+ case IP6T_HL_GT:
+ printf("HL > ");
+ break;
+ }
+ printf("%u ", info->hop_limit);
+}
+
+static void save(const struct ip6t_ip6 *ip,
+ const struct ip6t_entry_match *match)
+{
+ const struct ip6t_hl_info *info =
+ (struct ip6t_hl_info *) match->data;
+
+ switch (info->mode) {
+ case IP6T_HL_EQ:
+ printf("--hl-eq ");
+ break;
+ case IP6T_HL_NE:
+ printf("! --hl-eq ");
+ break;
+ case IP6T_HL_LT:
+ printf("--hl-lt ");
+ break;
+ case IP6T_HL_GT:
+ printf("--hl-gt ");
+ break;
+ default:
+ /* error */
+ break;
+ }
+ printf("%u ", info->hop_limit);
+}
+
+static struct option opts[] = {
+ { "hl", 1, 0, '2' },
+ { "hl-eq", 1, 0, '2'},
+ { "hl-lt", 1, 0, '3'},
+ { "hl-gt", 1, 0, '4'},
+ { 0 }
+};
+
+static
+struct ip6tables_match hl = {
+ NULL,
+ "hl",
+ IPTABLES_VERSION,
+ IP6T_ALIGN(sizeof(struct ip6t_hl_info)),
+ IP6T_ALIGN(sizeof(struct ip6t_hl_info)),
+ &help,
+ &init,
+ &parse,
+ &final_check,
+ &print,
+ &save,
+ opts
+};
+
+
+void _init(void)
+{
+ register_match6(&hl);
+}