from Grzegorz Borowiak

diff --git a/extensions/ebt_arpreply.c b/extensions/ebt_arpreply.c
new file mode 100644 (file)
index 0000000..0cbc630
--- /dev/null
+++ b/extensions/ebt_arpreply.c
@@ -0,0 +1,132 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <netinet/ether.h>
+#include <getopt.h>
+#include "../include/ebtables_u.h"
+#include <linux/netfilter_bridge/ebt_arpreply.h>
+
+static int mac_supplied;
+
+#define REPLY_MAC '1'
+#define REPLY_TARGET '2'
+static struct option opts[] =
+{
+       { "arpreply-mac" ,    required_argument, 0, REPLY_MAC    },
+       { "arpreply-target" , required_argument, 0, REPLY_TARGET },
+       { 0 }
+};
+
+static void print_help()
+{
+       printf(
+       "arpreply target options:\n"
+       " --arpreply-mac address           : source MAC of generated reply\n"
+       " --arpreply-target target         : ACCEPT, DROP, RETURN or CONTINUE\n"
+       "                                    (standard target is DROP)\n");
+}
+
+static void init(struct ebt_entry_target *target)
+{
+       struct ebt_arpreply_info *replyinfo =
+          (struct ebt_arpreply_info *)target->data;
+
+       replyinfo->target = EBT_DROP;
+       memset(replyinfo->mac, 0, ETH_ALEN);
+       mac_supplied = 0;
+}
+
+#define OPT_REPLY_MAC     0x01
+#define OPT_REPLY_TARGET  0x02
+static int parse(int c, char **argv, int argc,
+   const struct ebt_u_entry *entry, unsigned int *flags,
+   struct ebt_entry_target **target)
+{
+       struct ebt_arpreply_info *replyinfo =
+          (struct ebt_arpreply_info *)(*target)->data;
+       struct ether_addr *addr;
+
+       switch (c) {
+       case REPLY_MAC:
+               check_option(flags, OPT_REPLY_MAC);
+               if (!(addr = ether_aton(optarg)))
+                       print_error("Problem with specified "
+                                   "--arpreply-mac mac");
+               memcpy(replyinfo->mac, addr, ETH_ALEN);
+               mac_supplied = 1;
+               break;
+       case REPLY_TARGET:
+               check_option(flags, OPT_REPLY_TARGET);
+               if (FILL_TARGET(optarg, replyinfo->target))
+                       print_error("Illegal --arpreply-target target");
+               break;
+
+       default:
+               return 0;
+       }
+       return 1;
+}
+
+static void final_check(const struct ebt_u_entry *entry,
+   const struct ebt_entry_target *target, const char *name,
+   unsigned int hookmask, unsigned int time)
+{
+       struct ebt_arpreply_info *replyinfo =
+          (struct ebt_arpreply_info *)target->data;
+
+       if (entry->ethproto != ETH_P_ARP || entry->invflags & EBT_IPROTO)
+               print_error("For ARP replying the protocol must be "
+                           "specified as ARP");
+       if (time == 0 && mac_supplied == 0)
+               print_error("No arpreply mac supplied");
+       if (BASE_CHAIN && replyinfo->target == EBT_RETURN)
+               print_error("--arpreply-target RETURN not allowed on "
+                           "base chain");
+       CLEAR_BASE_CHAIN_BIT;
+       if (strcmp(name, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING))
+               print_error("arpreply only allowed in PREROUTING");
+}
+
+static void print(const struct ebt_u_entry *entry,
+   const struct ebt_entry_target *target)
+{
+       struct ebt_arpreply_info *replyinfo =
+          (struct ebt_arpreply_info *)target->data;
+
+       printf("--arpreply-mac ");
+       print_mac(replyinfo->mac);
+       if (replyinfo->target == EBT_DROP)
+               return;
+       printf(" --arpreply-target %s", TARGET_NAME(replyinfo->target));
+}
+
+static int compare(const struct ebt_entry_target *t1,
+   const struct ebt_entry_target *t2)
+{
+       struct ebt_arpreply_info *replyinfo1 =
+          (struct ebt_arpreply_info *)t1->data;
+       struct ebt_arpreply_info *replyinfo2 =
+          (struct ebt_arpreply_info *)t2->data;
+
+       return memcmp(replyinfo1->mac, replyinfo2->mac, ETH_ALEN) == 0
+               && replyinfo1->target == replyinfo2->target;
+}
+
+static struct ebt_u_target arpreply_target =
+{
+       EBT_ARPREPLY_TARGET,
+       sizeof(struct ebt_arpreply_info),
+       print_help,
+       init,
+       parse,
+       final_check,
+       print,
+       compare,
+       opts
+};
+
+static void _init(void) __attribute__ ((constructor));
+static void _init(void)
+{
+       register_target(&arpreply_target);
+}