1/*
2 * WPA Supplicant - Layer2 packet interface definition
3 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 *
8 * This file defines an interface for layer 2 (link layer) packet sending and
9 * receiving. l2_packet_linux.c is one implementation for such a layer 2
10 * implementation using Linux packet sockets and l2_packet_pcap.c another one
11 * using libpcap and libdnet. When porting %wpa_supplicant to other operating
12 * systems, a new l2_packet implementation may need to be added.
13 */
14
15#ifndef L2_PACKET_H
16#define L2_PACKET_H
17
18/**
19 * struct l2_packet_data - Internal l2_packet data structure
20 *
21 * This structure is used by the l2_packet implementation to store its private
22 * data. Other files use a pointer to this data when calling the l2_packet
23 * functions, but the contents of this structure should not be used directly
24 * outside l2_packet implementation.
25 */
26struct l2_packet_data;
27
28#ifdef _MSC_VER
29#pragma pack(push, 1)
30#endif /* _MSC_VER */
31
32struct l2_ethhdr {
33	u8 h_dest[ETH_ALEN];
34	u8 h_source[ETH_ALEN];
35	be16 h_proto;
36} STRUCT_PACKED;
37
38#ifdef _MSC_VER
39#pragma pack(pop)
40#endif /* _MSC_VER */
41
42/**
43 * l2_packet_init - Initialize l2_packet interface
44 * @ifname: Interface name
45 * @own_addr: Optional own MAC address if available from driver interface or
46 *	%NULL if not available
47 * @protocol: Ethernet protocol number in host byte order
48 * @rx_callback: Callback function that will be called for each received packet
49 * @rx_callback_ctx: Callback data (ctx) for calls to rx_callback()
50 * @l2_hdr: 1 = include layer 2 header, 0 = do not include header
51 * Returns: Pointer to internal data or %NULL on failure
52 *
53 * rx_callback function will be called with src_addr pointing to the source
54 * address (MAC address) of the the packet. If l2_hdr is set to 0, buf
55 * points to len bytes of the payload after the layer 2 header and similarly,
56 * TX buffers start with payload. This behavior can be changed by setting
57 * l2_hdr=1 to include the layer 2 header in the data buffer.
58 */
59struct l2_packet_data * l2_packet_init(
60	const char *ifname, const u8 *own_addr, unsigned short protocol,
61	void (*rx_callback)(void *ctx, const u8 *src_addr,
62			    const u8 *buf, size_t len),
63	void *rx_callback_ctx, int l2_hdr);
64
65/**
66 * l2_packet_deinit - Deinitialize l2_packet interface
67 * @l2: Pointer to internal l2_packet data from l2_packet_init()
68 */
69void l2_packet_deinit(struct l2_packet_data *l2);
70
71/**
72 * l2_packet_get_own_addr - Get own layer 2 address
73 * @l2: Pointer to internal l2_packet data from l2_packet_init()
74 * @addr: Buffer for the own address (6 bytes)
75 * Returns: 0 on success, -1 on failure
76 */
77int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr);
78
79/**
80 * l2_packet_send - Send a packet
81 * @l2: Pointer to internal l2_packet data from l2_packet_init()
82 * @dst_addr: Destination address for the packet (only used if l2_hdr == 0)
83 * @proto: Protocol/ethertype for the packet in host byte order (only used if
84 * l2_hdr == 0)
85 * @buf: Packet contents to be sent; including layer 2 header if l2_hdr was
86 * set to 1 in l2_packet_init() call. Otherwise, only the payload of the packet
87 * is included.
88 * @len: Length of the buffer (including l2 header only if l2_hdr == 1)
89 * Returns: >=0 on success, <0 on failure
90 */
91int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
92		   const u8 *buf, size_t len);
93
94/**
95 * l2_packet_get_ip_addr - Get the current IP address from the interface
96 * @l2: Pointer to internal l2_packet data from l2_packet_init()
97 * @buf: Buffer for the IP address in text format
98 * @len: Maximum buffer length
99 * Returns: 0 on success, -1 on failure
100 *
101 * This function can be used to get the current IP address from the interface
102 * bound to the l2_packet. This is mainly for status information and the IP
103 * address will be stored as an ASCII string. This function is not essential
104 * for %wpa_supplicant operation, so full implementation is not required.
105 * l2_packet implementation will need to define the function, but it can return
106 * -1 if the IP address information is not available.
107 */
108int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len);
109
110
111/**
112 * l2_packet_notify_auth_start - Notify l2_packet about start of authentication
113 * @l2: Pointer to internal l2_packet data from l2_packet_init()
114 *
115 * This function is called when authentication is expected to start, e.g., when
116 * association has been completed, in order to prepare l2_packet implementation
117 * for EAPOL frames. This function is used mainly if the l2_packet code needs
118 * to do polling in which case it can increasing polling frequency. This can
119 * also be an empty function if the l2_packet implementation does not benefit
120 * from knowing about the starting authentication.
121 */
122void l2_packet_notify_auth_start(struct l2_packet_data *l2);
123
124#endif /* L2_PACKET_H */
125