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* WPA Supplicant - Layer2 packet interface definition
* Copyright (c) 2003-2005, Jouni Malinen <>
* This software may be distributed under the terms of the BSD license.
* See README for more details.
* This file defines an interface for layer 2 (link layer) packet sending and
* receiving. l2_packet_linux.c is one implementation for such a layer 2
* implementation using Linux packet sockets and l2_packet_pcap.c another one
* using libpcap and libdnet. When porting %wpa_supplicant to other operating
* systems, a new l2_packet implementation may need to be added.
#ifndef L2_PACKET_H
#define L2_PACKET_H
* struct l2_packet_data - Internal l2_packet data structure
* This structure is used by the l2_packet implementation to store its private
* data. Other files use a pointer to this data when calling the l2_packet
* functions, but the contents of this structure should not be used directly
* outside l2_packet implementation.
struct l2_packet_data;
#ifdef _MSC_VER
#pragma pack(push, 1)
#endif /* _MSC_VER */
struct l2_ethhdr {
u8 h_dest[ETH_ALEN];
u8 h_source[ETH_ALEN];
be16 h_proto;
#ifdef _MSC_VER
#pragma pack(pop)
#endif /* _MSC_VER */
* l2_packet_init - Initialize l2_packet interface
* @ifname: Interface name
* @own_addr: Optional own MAC address if available from driver interface or
* %NULL if not available
* @protocol: Ethernet protocol number in host byte order
* @rx_callback: Callback function that will be called for each received packet
* @rx_callback_ctx: Callback data (ctx) for calls to rx_callback()
* @l2_hdr: 1 = include layer 2 header, 0 = do not include header
* Returns: Pointer to internal data or %NULL on failure
* rx_callback function will be called with src_addr pointing to the source
* address (MAC address) of the the packet. If l2_hdr is set to 0, buf
* points to len bytes of the payload after the layer 2 header and similarly,
* TX buffers start with payload. This behavior can be changed by setting
* l2_hdr=1 to include the layer 2 header in the data buffer.
struct l2_packet_data * l2_packet_init(
const char *ifname, const u8 *own_addr, unsigned short protocol,
void (*rx_callback)(void *ctx, const u8 *src_addr,
const u8 *buf, size_t len),
void *rx_callback_ctx, int l2_hdr);
* l2_packet_deinit - Deinitialize l2_packet interface
* @l2: Pointer to internal l2_packet data from l2_packet_init()
void l2_packet_deinit(struct l2_packet_data *l2);
* l2_packet_get_own_addr - Get own layer 2 address
* @l2: Pointer to internal l2_packet data from l2_packet_init()
* @addr: Buffer for the own address (6 bytes)
* Returns: 0 on success, -1 on failure
int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr);
* l2_packet_send - Send a packet
* @l2: Pointer to internal l2_packet data from l2_packet_init()
* @dst_addr: Destination address for the packet (only used if l2_hdr == 0)
* @proto: Protocol/ethertype for the packet in host byte order (only used if
* l2_hdr == 0)
* @buf: Packet contents to be sent; including layer 2 header if l2_hdr was
* set to 1 in l2_packet_init() call. Otherwise, only the payload of the packet
* is included.
* @len: Length of the buffer (including l2 header only if l2_hdr == 1)
* Returns: >=0 on success, <0 on failure
int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
const u8 *buf, size_t len);
* l2_packet_get_ip_addr - Get the current IP address from the interface
* @l2: Pointer to internal l2_packet data from l2_packet_init()
* @buf: Buffer for the IP address in text format
* @len: Maximum buffer length
* Returns: 0 on success, -1 on failure
* This function can be used to get the current IP address from the interface
* bound to the l2_packet. This is mainly for status information and the IP
* address will be stored as an ASCII string. This function is not essential
* for %wpa_supplicant operation, so full implementation is not required.
* l2_packet implementation will need to define the function, but it can return
* -1 if the IP address information is not available.
int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len);
* l2_packet_notify_auth_start - Notify l2_packet about start of authentication
* @l2: Pointer to internal l2_packet data from l2_packet_init()
* This function is called when authentication is expected to start, e.g., when
* association has been completed, in order to prepare l2_packet implementation
* for EAPOL frames. This function is used mainly if the l2_packet code needs
* to do polling in which case it can increasing polling frequency. This can
* also be an empty function if the l2_packet implementation does not benefit
* from knowing about the starting authentication.
void l2_packet_notify_auth_start(struct l2_packet_data *l2);
#endif /* L2_PACKET_H */