1 files changed, 170 insertions, 0 deletions
diff --git a/extensions/libipt_ah.c b/extensions/libipt_ah.c
new file mode 100644
index 0000000..170cd8b
--- /dev/null
+++ b/extensions/libipt_ah.c
@@ -0,0 +1,170 @@
+/* Shared library add-on to iptables to add AH support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <errno.h>
+#include <xtables.h>
+#include <linux/netfilter_ipv4/ipt_ah.h>
+
+static void ah_help(void)
+{
+	printf(
+"ah match options:\n"
+"[!] --ahspi spi[:spi]\n"
+"				match spi (range)\n");
+}
+
+static const struct option ah_opts[] = {
+	{ "ahspi", 1, NULL, '1' },
+	{ .name = NULL }
+};
+
+static u_int32_t
+parse_ah_spi(const char *spistr)
+{
+	unsigned long int spi;
+	char* ep;
+
+	spi =  strtoul(spistr,&ep,0) ;
+
+	if ( spistr == ep ) {
+		xtables_error(PARAMETER_PROBLEM,
+			   "AH no valid digits in spi `%s'", spistr);
+	}
+	if ( spi == ULONG_MAX  && errno == ERANGE ) {
+		xtables_error(PARAMETER_PROBLEM,
+			   "spi `%s' specified too big: would overflow", spistr);
+	}	
+	if ( *spistr != '\0'  && *ep != '\0' ) {
+		xtables_error(PARAMETER_PROBLEM,
+			   "AH error parsing spi `%s'", spistr);
+	}
+	return spi;
+}
+
+static void
+parse_ah_spis(const char *spistring, u_int32_t *spis)
+{
+	char *buffer;
+	char *cp;
+
+	buffer = strdup(spistring);
+	if ((cp = strchr(buffer, ':')) == NULL)
+		spis[0] = spis[1] = parse_ah_spi(buffer);
+	else {
+		*cp = '\0';
+		cp++;
+
+		spis[0] = buffer[0] ? parse_ah_spi(buffer) : 0;
+		spis[1] = cp[0] ? parse_ah_spi(cp) : 0xFFFFFFFF;
+	}
+	free(buffer);
+}
+
+static void ah_init(struct xt_entry_match *m)
+{
+	struct ipt_ah *ahinfo = (struct ipt_ah *)m->data;
+
+	ahinfo->spis[1] = 0xFFFFFFFF;
+}
+
+#define AH_SPI 0x01
+
+static int ah_parse(int c, char **argv, int invert, unsigned int *flags,
+                    const void *entry, struct xt_entry_match **match)
+{
+	struct ipt_ah *ahinfo = (struct ipt_ah *)(*match)->data;
+
+	switch (c) {
+	case '1':
+		if (*flags & AH_SPI)
+			xtables_error(PARAMETER_PROBLEM,
+				   "Only one `--ahspi' allowed");
+		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
+		parse_ah_spis(optarg, ahinfo->spis);
+		if (invert)
+			ahinfo->invflags |= IPT_AH_INV_SPI;
+		*flags |= AH_SPI;
+		break;
+	default:
+		return 0;
+	}
+
+	return 1;
+}
+
+static void
+print_spis(const char *name, u_int32_t min, u_int32_t max,
+	    int invert)
+{
+	const char *inv = invert ? "!" : "";
+
+	if (min != 0 || max != 0xFFFFFFFF || invert) {
+		printf("%s", name);
+		if (min == max) {
+			printf(":%s", inv);
+			printf("%u", min);
+		} else {
+			printf("s:%s", inv);
+			printf("%u",min);
+			printf(":");
+			printf("%u",max);
+		}
+		printf(" ");
+	}
+}
+
+static void ah_print(const void *ip, const struct xt_entry_match *match,
+                     int numeric)
+{
+	const struct ipt_ah *ah = (struct ipt_ah *)match->data;
+
+	printf("ah ");
+	print_spis("spi", ah->spis[0], ah->spis[1],
+		    ah->invflags & IPT_AH_INV_SPI);
+	if (ah->invflags & ~IPT_AH_INV_MASK)
+		printf("Unknown invflags: 0x%X ",
+		       ah->invflags & ~IPT_AH_INV_MASK);
+}
+
+static void ah_save(const void *ip, const struct xt_entry_match *match)
+{
+	const struct ipt_ah *ahinfo = (struct ipt_ah *)match->data;
+
+	if (!(ahinfo->spis[0] == 0
+	    && ahinfo->spis[1] == 0xFFFFFFFF)) {
+		printf("%s--ahspi ",
+			(ahinfo->invflags & IPT_AH_INV_SPI) ? "! " : "");
+		if (ahinfo->spis[0]
+		    != ahinfo->spis[1])
+			printf("%u:%u ",
+			       ahinfo->spis[0],
+			       ahinfo->spis[1]);
+		else
+			printf("%u ",
+			       ahinfo->spis[0]);
+	}
+
+}
+
+static struct xtables_match ah_mt_reg = {
+	.name 		= "ah",
+	.version 	= XTABLES_VERSION,
+	.family		= NFPROTO_IPV4,
+	.size		= XT_ALIGN(sizeof(struct ipt_ah)),
+	.userspacesize 	= XT_ALIGN(sizeof(struct ipt_ah)),
+	.help 		= ah_help,
+	.init 		= ah_init,
+	.parse 		= ah_parse,
+	.print 		= ah_print,
+	.save 		= ah_save,
+	.extra_opts 	= ah_opts,
+};
+
+void
+_init(void)
+{
+	xtables_register_match(&ah_mt_reg);
+}