fragattacks/src/ap/x_snoop.c

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/*
* Generic Snooping for Proxy ARP
* Copyright (c) 2014, Qualcomm Atheros, Inc.
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "hostapd.h"
#include "sta_info.h"
#include "ap_drv_ops.h"
#include "x_snoop.h"
int x_snoop_init(struct hostapd_data *hapd)
{
struct hostapd_bss_config *conf = hapd->conf;
if (!conf->isolate) {
wpa_printf(MSG_DEBUG,
"x_snoop: ap_isolate must be enabled for x_snoop");
return -1;
}
if (conf->bridge[0] == '\0') {
wpa_printf(MSG_DEBUG,
"x_snoop: Bridge must be configured for x_snoop");
return -1;
}
if (hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_HAIRPIN_MODE,
1)) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to enable hairpin_mode on the bridge port");
return -1;
}
if (hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_PROXYARP, 1)) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to enable proxyarp on the bridge port");
return -1;
}
if (hostapd_drv_br_set_net_param(hapd, DRV_BR_NET_PARAM_GARP_ACCEPT,
1)) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to enable accepting gratuitous ARP on the bridge");
return -1;
}
return 0;
}
struct l2_packet_data *
x_snoop_get_l2_packet(struct hostapd_data *hapd,
void (*handler)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len),
enum l2_packet_filter_type type)
{
struct hostapd_bss_config *conf = hapd->conf;
struct l2_packet_data *l2;
l2 = l2_packet_init(conf->bridge, NULL, ETH_P_ALL, handler, hapd, 1);
if (l2 == NULL) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to initialize L2 packet processing %s",
strerror(errno));
return NULL;
}
if (l2_packet_set_packet_filter(l2, type)) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to set L2 packet filter for type: %d",
type);
l2_packet_deinit(l2);
return NULL;
}
return l2;
}
void x_snoop_mcast_to_ucast_convert_send(struct hostapd_data *hapd,
struct sta_info *sta, u8 *buf,
size_t len)
{
int res;
u8 addr[ETH_ALEN];
u8 *dst_addr = buf;
if (!(dst_addr[0] & 0x01))
return;
wpa_printf(MSG_EXCESSIVE, "x_snoop: Multicast-to-unicast conversion "
MACSTR " -> " MACSTR " (len %u)",
MAC2STR(dst_addr), MAC2STR(sta->addr), (unsigned int) len);
/* save the multicast destination address for restoring it later */
os_memcpy(addr, buf, ETH_ALEN);
os_memcpy(buf, sta->addr, ETH_ALEN);
res = l2_packet_send(hapd->sock_dhcp, NULL, 0, buf, len);
if (res) {
wpa_printf(MSG_DEBUG,
"x_snoop: Failed to send mcast to ucast converted packet to "
MACSTR, MAC2STR(sta->addr));
}
/* restore the multicast destination address */
os_memcpy(buf, addr, ETH_ALEN);
}
void x_snoop_deinit(struct hostapd_data *hapd)
{
hostapd_drv_br_set_net_param(hapd, DRV_BR_NET_PARAM_GARP_ACCEPT, 0);
hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_PROXYARP, 0);
hostapd_drv_br_port_set_attr(hapd, DRV_BR_PORT_ATTR_HAIRPIN_MODE, 0);
}