Chris Vitale <cvs_at_bluetail.com>

1 files changed, 145 insertions, 0 deletions

diff --git a/extensions/ebt_802_3.c b/extensions/ebt_802_3.c
new file mode 100644
index 0000000..953a115
--- /dev/null
+++ b/extensions/ebt_802_3.c
@@ -0,0 +1,145 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include "../include/ebtables_u.h"
+#include "../include/ethernetdb.h"
+#include <linux/netfilter_bridge/ebt_802_3.h>
+
+#define _802_3_SAP '1'
+#define _802_3_TYPE '2'
+
+static struct option opts[] =
+{
+	{ "802_3-sap"   , required_argument, 0, _802_3_SAP },
+	{ "802_3-type"  , required_argument, 0, _802_3_TYPE },
+	{ 0 }
+};
+
+static void print_help()
+{
+	printf(
+"802_3 options:\n"
+"--802_3-sap [!] protocol       : 802.3 DSAP/SSAP- 1 byte value (hex)\n"
+"  DSAP and SSAP are always the same.  One SAP applies to both fields\n"
+"--802_3-type [!] protocol      : 802.3 SNAP Type- 2 byte value (hex)\n"
+"  Type implies SAP value 0xaa\n");
+}
+
+static void init(struct ebt_entry_match *match)
+{
+	struct ebt_802_3_info *info = (struct ebt_802_3_info *)match->data;
+
+	info->invflags = 0;
+	info->bitmask = 0;
+}
+
+static int parse(int c, char **argv, int argc, const struct ebt_u_entry *entry,
+   unsigned int *flags, struct ebt_entry_match **match)
+{
+	struct ebt_802_3_info *info = (struct ebt_802_3_info *) (*match)->data;
+	unsigned int i;
+	char *end;
+
+	switch (c) {
+		case _802_3_SAP:
+			check_option(flags, _802_3_SAP);
+			if (check_inverse(optarg))
+				info->invflags |= EBT_802_3_SAP;
+
+			if (optind > argc)
+				print_error("Missing 802.3-sap argument");
+			i = strtoul(argv[optind - 1], &end, 16);
+			if (i > 255 || *end != '\0') 
+				print_error("Problem with specified "
+				            "sap hex value, %x",i);
+			info->sap = i; /* one byte, so no byte order worries */
+			info->bitmask |= EBT_802_3_SAP;
+			break;
+		case _802_3_TYPE:
+			check_option(flags, _802_3_TYPE);
+			if (check_inverse(optarg))
+				info->invflags |= EBT_802_3_TYPE;
+			if (optind > argc)
+				print_error("Missing 802.3-type argument");
+			i = strtoul(argv[optind - 1], &end, 16);
+			if (i > 65535 || *end != '\0') {
+				print_error("Problem with the specified "
+					    "type hex value, %x",i);
+			}
+			info->type = htons(i);
+			info->bitmask |= EBT_802_3_TYPE;
+			break;
+		default:
+			return 0;
+	}
+	return 1;
+}
+
+static void final_check(const struct ebt_u_entry *entry,
+   const struct ebt_entry_match *match, const char *name,
+   unsigned int hookmask, unsigned int time)
+{
+	if (!(entry->bitmask & EBT_802_3))
+		print_error("For 802.3 DSAP/SSAP filtering the protocol "
+			    "must be LENGTH");
+}
+
+static void print(const struct ebt_u_entry *entry,
+   const struct ebt_entry_match *match)
+{
+	struct ebt_802_3_info *info = (struct ebt_802_3_info *)match->data;
+
+	if (info->bitmask & EBT_802_3_SAP) {
+		printf("--802_3-sap ");
+		if (info->invflags & EBT_802_3_SAP)
+			printf("! ");
+		printf("0x%.2x ", info->sap);
+	}
+	if (info->bitmask & EBT_802_3_TYPE) {
+		printf("--802_3-type ");
+		if (info->invflags & EBT_802_3_TYPE)
+			printf("! ");
+		printf("0x%.4x ", ntohs(info->type));
+	}
+}
+
+static int compare(const struct ebt_entry_match *m1,
+   const struct ebt_entry_match *m2)
+{
+	struct ebt_802_3_info *info1 = (struct ebt_802_3_info *)m1->data;
+	struct ebt_802_3_info *info2 = (struct ebt_802_3_info *)m2->data;
+
+	if (info1->bitmask != info2->bitmask)
+		return 0;
+	if (info1->invflags != info2->invflags)
+		return 0;
+	if (info1->bitmask & EBT_802_3_SAP) {
+		if (info1->sap != info2->sap) 
+			return 0;
+	}
+	if (info1->bitmask & EBT_802_3_TYPE) {
+		if (info1->type != info2->type)
+			return 0;
+	}
+	return 1;
+}
+
+static struct ebt_u_match _802_3_match = 
+{
+	EBT_802_3_MATCH,
+	sizeof(struct ebt_802_3_info),
+	print_help,
+	init,
+	parse,
+	final_check,
+	print,
+	compare,
+	opts
+};
+
+static void _init(void) __attribute__ ((constructor));
+static void _init(void)
+{
+	        register_match(&_802_3_match);
+}