139 lines
3.6 KiB
C
139 lines
3.6 KiB
C
/* ebt_arpreply
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*
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* Authors:
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* Grzegorz Borowiak <grzes@gnu.univ.gda.pl>
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* Bart De Schuymer <bdschuym@pandora.be>
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*
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* August, 2003
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <getopt.h>
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#include "../include/ebtables_u.h"
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#include <netinet/ether.h>
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#include <linux/netfilter_bridge/ebt_arpreply.h>
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static int mac_supplied;
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#define REPLY_MAC '1'
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#define REPLY_TARGET '2'
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static struct option opts[] =
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{
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{ "arpreply-mac" , required_argument, 0, REPLY_MAC },
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{ "arpreply-target" , required_argument, 0, REPLY_TARGET },
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{ 0 }
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};
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static void print_help()
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{
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printf(
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"arpreply target options:\n"
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" --arpreply-mac address : source MAC of generated reply\n"
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" --arpreply-target target : ACCEPT, DROP, RETURN or CONTINUE\n"
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" (standard target is DROP)\n");
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}
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static void init(struct ebt_entry_target *target)
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{
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struct ebt_arpreply_info *replyinfo =
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(struct ebt_arpreply_info *)target->data;
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replyinfo->target = EBT_DROP;
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memset(replyinfo->mac, 0, ETH_ALEN);
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mac_supplied = 0;
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}
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#define OPT_REPLY_MAC 0x01
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#define OPT_REPLY_TARGET 0x02
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static int parse(int c, char **argv, int argc,
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const struct ebt_u_entry *entry, unsigned int *flags,
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struct ebt_entry_target **target)
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{
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struct ebt_arpreply_info *replyinfo =
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(struct ebt_arpreply_info *)(*target)->data;
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struct ether_addr *addr;
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switch (c) {
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case REPLY_MAC:
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ebt_check_option2(flags, OPT_REPLY_MAC);
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if (!(addr = ether_aton(optarg)))
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ebt_print_error2("Problem with specified --arpreply-mac mac");
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memcpy(replyinfo->mac, addr, ETH_ALEN);
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mac_supplied = 1;
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break;
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case REPLY_TARGET:
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ebt_check_option2(flags, OPT_REPLY_TARGET);
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if (FILL_TARGET(optarg, replyinfo->target))
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ebt_print_error2("Illegal --arpreply-target target");
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break;
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default:
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return 0;
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}
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return 1;
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}
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static void final_check(const struct ebt_u_entry *entry,
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const struct ebt_entry_target *target, const char *name,
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unsigned int hookmask, unsigned int time)
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{
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struct ebt_arpreply_info *replyinfo =
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(struct ebt_arpreply_info *)target->data;
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if (entry->ethproto != ETH_P_ARP || entry->invflags & EBT_IPROTO) {
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ebt_print_error("For ARP replying the protocol must be specified as ARP");
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} else if (time == 0 && mac_supplied == 0) {
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ebt_print_error("No arpreply mac supplied");
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} else if (BASE_CHAIN && replyinfo->target == EBT_RETURN) {
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ebt_print_error("--arpreply-target RETURN not allowed on base chain");
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} else {
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CLEAR_BASE_CHAIN_BIT;
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if (strcmp(name, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING))
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ebt_print_error("arpreply only allowed in PREROUTING");
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}
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}
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static void print(const struct ebt_u_entry *entry,
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const struct ebt_entry_target *target)
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{
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struct ebt_arpreply_info *replyinfo =
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(struct ebt_arpreply_info *)target->data;
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printf("--arpreply-mac ");
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ebt_print_mac(replyinfo->mac);
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if (replyinfo->target == EBT_DROP)
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return;
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printf(" --arpreply-target %s", TARGET_NAME(replyinfo->target));
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}
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static int compare(const struct ebt_entry_target *t1,
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const struct ebt_entry_target *t2)
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{
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struct ebt_arpreply_info *replyinfo1 =
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(struct ebt_arpreply_info *)t1->data;
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struct ebt_arpreply_info *replyinfo2 =
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(struct ebt_arpreply_info *)t2->data;
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return memcmp(replyinfo1->mac, replyinfo2->mac, ETH_ALEN) == 0
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&& replyinfo1->target == replyinfo2->target;
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}
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static struct ebt_u_target arpreply_target =
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{
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.name = "arpreply",
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.size = sizeof(struct ebt_arpreply_info),
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.help = print_help,
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.init = init,
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.parse = parse,
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.final_check = final_check,
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.print = print,
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.compare = compare,
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.extra_ops = opts,
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};
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void _arpreply_init(void)
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{
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ebt_register_target(&arpreply_target);
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}
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