l2_packet.h revision 8d520ff1dc2da35cdca849e982051b86468016d8 
1/*
2 * WPA Supplicant - Layer2 packet interface definition
3 * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Alternatively, this software may be distributed under the terms of BSD
10 * license.
11 *
12 * See README and COPYING for more details.
13 *
14 * This file defines an interface for layer 2 (link layer) packet sending and
15 * receiving. l2_packet_linux.c is one implementation for such a layer 2
16 * implementation using Linux packet sockets and l2_packet_pcap.c another one
17 * using libpcap and libdnet. When porting %wpa_supplicant to other operating
18 * systems, a new l2_packet implementation may need to be added.
19 */
20
21#ifndef L2_PACKET_H
22#define L2_PACKET_H
23
24/**
25 * struct l2_packet_data - Internal l2_packet data structure
26 *
27 * This structure is used by the l2_packet implementation to store its private
28 * data. Other files use a pointer to this data when calling the l2_packet
29 * functions, but the contents of this structure should not be used directly
30 * outside l2_packet implementation.
31 */
32struct l2_packet_data;
33
34#ifdef _MSC_VER
35#pragma pack(push, 1)
36#endif /* _MSC_VER */
37
38struct l2_ethhdr {
39	u8 h_dest[ETH_ALEN];
40	u8 h_source[ETH_ALEN];
41	be16 h_proto;
42} STRUCT_PACKED;
43
44#ifdef _MSC_VER
45#pragma pack(pop)
46#endif /* _MSC_VER */
47
48/**
49 * l2_packet_init - Initialize l2_packet interface
50 * @ifname: Interface name
51 * @own_addr: Optional own MAC address if available from driver interface or
52 *	%NULL if not available
53 * @protocol: Ethernet protocol number in host byte order
54 * @rx_callback: Callback function that will be called for each received packet
55 * @rx_callback_ctx: Callback data (ctx) for calls to rx_callback()
56 * @l2_hdr: 1 = include layer 2 header, 0 = do not include header
57 * Returns: Pointer to internal data or %NULL on failure
58 *
59 * rx_callback function will be called with src_addr pointing to the source
60 * address (MAC address) of the the packet. If l2_hdr is set to 0, buf
61 * points to len bytes of the payload after the layer 2 header and similarly,
62 * TX buffers start with payload. This behavior can be changed by setting
63 * l2_hdr=1 to include the layer 2 header in the data buffer.
64 */
65struct l2_packet_data * l2_packet_init(
66	const char *ifname, const u8 *own_addr, unsigned short protocol,
67	void (*rx_callback)(void *ctx, const u8 *src_addr,
68			    const u8 *buf, size_t len),
69	void *rx_callback_ctx, int l2_hdr);
70
71/**
72 * l2_packet_deinit - Deinitialize l2_packet interface
73 * @l2: Pointer to internal l2_packet data from l2_packet_init()
74 */
75void l2_packet_deinit(struct l2_packet_data *l2);
76
77/**
78 * l2_packet_get_own_addr - Get own layer 2 address
79 * @l2: Pointer to internal l2_packet data from l2_packet_init()
80 * @addr: Buffer for the own address (6 bytes)
81 * Returns: 0 on success, -1 on failure
82 */
83int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr);
84
85/**
86 * l2_packet_send - Send a packet
87 * @l2: Pointer to internal l2_packet data from l2_packet_init()
88 * @dst_addr: Destination address for the packet (only used if l2_hdr == 0)
89 * @proto: Protocol/ethertype for the packet in host byte order (only used if
90 * l2_hdr == 0)
91 * @buf: Packet contents to be sent; including layer 2 header if l2_hdr was
92 * set to 1 in l2_packet_init() call. Otherwise, only the payload of the packet
93 * is included.
94 * @len: Length of the buffer (including l2 header only if l2_hdr == 1)
95 * Returns: >=0 on success, <0 on failure
96 */
97int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
98		   const u8 *buf, size_t len);
99
100/**
101 * l2_packet_get_ip_addr - Get the current IP address from the interface
102 * @l2: Pointer to internal l2_packet data from l2_packet_init()
103 * @buf: Buffer for the IP address in text format
104 * @len: Maximum buffer length
105 * Returns: 0 on success, -1 on failure
106 *
107 * This function can be used to get the current IP address from the interface
108 * bound to the l2_packet. This is mainly for status information and the IP
109 * address will be stored as an ASCII string. This function is not essential
110 * for %wpa_supplicant operation, so full implementation is not required.
111 * l2_packet implementation will need to define the function, but it can return
112 * -1 if the IP address information is not available.
113 */
114int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len);
115
116
117/**
118 * l2_packet_notify_auth_start - Notify l2_packet about start of authentication
119 * @l2: Pointer to internal l2_packet data from l2_packet_init()
120 *
121 * This function is called when authentication is expected to start, e.g., when
122 * association has been completed, in order to prepare l2_packet implementation
123 * for EAPOL frames. This function is used mainly if the l2_packet code needs
124 * to do polling in which case it can increasing polling frequency. This can
125 * also be an empty function if the l2_packet implementation does not benefit
126 * from knowing about the starting authentication.
127 */
128void l2_packet_notify_auth_start(struct l2_packet_data *l2);
129
130#endif /* L2_PACKET_H */
131