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-rw-r--r--src/l2_packet/l2_packet_linux.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/src/l2_packet/l2_packet_linux.c b/src/l2_packet/l2_packet_linux.c
index 1419830..fcbf7e0 100644
--- a/src/l2_packet/l2_packet_linux.c
+++ b/src/l2_packet/l2_packet_linux.c
@@ -10,6 +10,7 @@
#include <sys/ioctl.h>
#include <netpacket/packet.h>
#include <net/if.h>
+#include <linux/filter.h>
#include "common.h"
#include "eloop.h"
@@ -28,6 +29,32 @@ struct l2_packet_data {
* buffers */
};
+/* Generated by 'sudo tcpdump -s 3000 -dd greater 278 and ip and udp and
+ * src port bootps and dst port bootpc'
+ */
+static struct sock_filter dhcp_sock_filter_insns[] = {
+ { 0x80, 0, 0, 0x00000000 },
+ { 0x35, 0, 12, 0x00000116 },
+ { 0x28, 0, 0, 0x0000000c },
+ { 0x15, 0, 10, 0x00000800 },
+ { 0x30, 0, 0, 0x00000017 },
+ { 0x15, 0, 8, 0x00000011 },
+ { 0x28, 0, 0, 0x00000014 },
+ { 0x45, 6, 0, 0x00001fff },
+ { 0xb1, 0, 0, 0x0000000e },
+ { 0x48, 0, 0, 0x0000000e },
+ { 0x15, 0, 3, 0x00000043 },
+ { 0x48, 0, 0, 0x00000010 },
+ { 0x15, 0, 1, 0x00000044 },
+ { 0x6, 0, 0, 0x00000bb8 },
+ { 0x6, 0, 0, 0x00000000 },
+};
+
+static const struct sock_fprog dhcp_sock_filter = {
+ .len = ARRAY_SIZE(dhcp_sock_filter_insns),
+ .filter = dhcp_sock_filter_insns,
+};
+
int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr)
{
@@ -202,3 +229,28 @@ int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len)
void l2_packet_notify_auth_start(struct l2_packet_data *l2)
{
}
+
+
+int l2_packet_set_packet_filter(struct l2_packet_data *l2,
+ enum l2_packet_filter_type type)
+{
+ const struct sock_fprog *sock_filter;
+
+ switch (type) {
+ case L2_PACKET_FILTER_DHCP:
+ sock_filter = &dhcp_sock_filter;
+ break;
+ default:
+ return -1;
+ }
+
+ if (setsockopt(l2->fd, SOL_SOCKET, SO_ATTACH_FILTER,
+ sock_filter, sizeof(struct sock_fprog))) {
+ wpa_printf(MSG_ERROR,
+ "l2_packet_linux: setsockopt(SO_ATTACH_FILTER) failed: %s",
+ strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}