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
42enum l2_packet_filter_type {
43	L2_PACKET_FILTER_DHCP,
44	L2_PACKET_FILTER_NDISC,
45	L2_PACKET_FILTER_PKTTYPE,
46};
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_init_bridge - Like l2_packet_init() but with bridge workaround
73 *
74 * This version of l2_packet_init() can be used to enable a workaround for Linux
75 * packet socket in case of a station interface in a bridge.
76 */
77struct l2_packet_data * l2_packet_init_bridge(
78	const char *br_ifname, const char *ifname, const u8 *own_addr,
79	unsigned short protocol,
80	void (*rx_callback)(void *ctx, const u8 *src_addr,
81			    const u8 *buf, size_t len),
82	void *rx_callback_ctx, int l2_hdr);
83
84/**
85 * l2_packet_deinit - Deinitialize l2_packet interface
86 * @l2: Pointer to internal l2_packet data from l2_packet_init()
87 */
88void l2_packet_deinit(struct l2_packet_data *l2);
89
90/**
91 * l2_packet_get_own_addr - Get own layer 2 address
92 * @l2: Pointer to internal l2_packet data from l2_packet_init()
93 * @addr: Buffer for the own address (6 bytes)
94 * Returns: 0 on success, -1 on failure
95 */
96int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr);
97
98/**
99 * l2_packet_send - Send a packet
100 * @l2: Pointer to internal l2_packet data from l2_packet_init()
101 * @dst_addr: Destination address for the packet (only used if l2_hdr == 0)
102 * @proto: Protocol/ethertype for the packet in host byte order (only used if
103 * l2_hdr == 0)
104 * @buf: Packet contents to be sent; including layer 2 header if l2_hdr was
105 * set to 1 in l2_packet_init() call. Otherwise, only the payload of the packet
106 * is included.
107 * @len: Length of the buffer (including l2 header only if l2_hdr == 1)
108 * Returns: >=0 on success, <0 on failure
109 */
110int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto,
111		   const u8 *buf, size_t len);
112
113/**
114 * l2_packet_get_ip_addr - Get the current IP address from the interface
115 * @l2: Pointer to internal l2_packet data from l2_packet_init()
116 * @buf: Buffer for the IP address in text format
117 * @len: Maximum buffer length
118 * Returns: 0 on success, -1 on failure
119 *
120 * This function can be used to get the current IP address from the interface
121 * bound to the l2_packet. This is mainly for status information and the IP
122 * address will be stored as an ASCII string. This function is not essential
123 * for %wpa_supplicant operation, so full implementation is not required.
124 * l2_packet implementation will need to define the function, but it can return
125 * -1 if the IP address information is not available.
126 */
127int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len);
128
129
130/**
131 * l2_packet_notify_auth_start - Notify l2_packet about start of authentication
132 * @l2: Pointer to internal l2_packet data from l2_packet_init()
133 *
134 * This function is called when authentication is expected to start, e.g., when
135 * association has been completed, in order to prepare l2_packet implementation
136 * for EAPOL frames. This function is used mainly if the l2_packet code needs
137 * to do polling in which case it can increasing polling frequency. This can
138 * also be an empty function if the l2_packet implementation does not benefit
139 * from knowing about the starting authentication.
140 */
141void l2_packet_notify_auth_start(struct l2_packet_data *l2);
142
143/**
144 * l2_packet_set_packet_filter - Set socket filter for l2_packet
145 * @l2: Pointer to internal l2_packet data from l2_packet_init()
146 * @type: enum l2_packet_filter_type, type of filter
147 * Returns: 0 on success, -1 on failure
148 *
149 * This function is used to set the socket filter for l2_packet socket.
150 *
151 */
152int l2_packet_set_packet_filter(struct l2_packet_data *l2,
153				enum l2_packet_filter_type type);
154
155#endif /* L2_PACKET_H */
156