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 */ 26 struct l2_packet_data; 27 28 #ifdef _MSC_VER 29 #pragma pack(push, 1) 30 #endif /* _MSC_VER */ 31 32 struct 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 enum 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 * 65 * IF rx_callback is NULL, receive operation is not opened at all, i.e., only 66 * the TX path and additional helper functions for fetching MAC and IP 67 * addresses can be used. 68 */ 69 struct l2_packet_data * l2_packet_init( 70 const char *ifname, const u8 *own_addr, unsigned short protocol, 71 void (*rx_callback)(void *ctx, const u8 *src_addr, 72 const u8 *buf, size_t len), 73 void *rx_callback_ctx, int l2_hdr); 74 75 /** 76 * l2_packet_init_bridge - Like l2_packet_init() but with bridge workaround 77 * 78 * This version of l2_packet_init() can be used to enable a workaround for Linux 79 * packet socket in case of a station interface in a bridge. 80 */ 81 struct l2_packet_data * l2_packet_init_bridge( 82 const char *br_ifname, const char *ifname, const u8 *own_addr, 83 unsigned short protocol, 84 void (*rx_callback)(void *ctx, const u8 *src_addr, 85 const u8 *buf, size_t len), 86 void *rx_callback_ctx, int l2_hdr); 87 88 /** 89 * l2_packet_deinit - Deinitialize l2_packet interface 90 * @l2: Pointer to internal l2_packet data from l2_packet_init() 91 */ 92 void l2_packet_deinit(struct l2_packet_data *l2); 93 94 /** 95 * l2_packet_get_own_addr - Get own layer 2 address 96 * @l2: Pointer to internal l2_packet data from l2_packet_init() 97 * @addr: Buffer for the own address (6 bytes) 98 * Returns: 0 on success, -1 on failure 99 */ 100 int l2_packet_get_own_addr(struct l2_packet_data *l2, u8 *addr); 101 102 /** 103 * l2_packet_send - Send a packet 104 * @l2: Pointer to internal l2_packet data from l2_packet_init() 105 * @dst_addr: Destination address for the packet (only used if l2_hdr == 0) 106 * @proto: Protocol/ethertype for the packet in host byte order (only used if 107 * l2_hdr == 0) 108 * @buf: Packet contents to be sent; including layer 2 header if l2_hdr was 109 * set to 1 in l2_packet_init() call. Otherwise, only the payload of the packet 110 * is included. 111 * @len: Length of the buffer (including l2 header only if l2_hdr == 1) 112 * Returns: >=0 on success, <0 on failure 113 */ 114 int l2_packet_send(struct l2_packet_data *l2, const u8 *dst_addr, u16 proto, 115 const u8 *buf, size_t len); 116 117 /** 118 * l2_packet_get_ip_addr - Get the current IP address from the interface 119 * @l2: Pointer to internal l2_packet data from l2_packet_init() 120 * @buf: Buffer for the IP address in text format 121 * @len: Maximum buffer length 122 * Returns: 0 on success, -1 on failure 123 * 124 * This function can be used to get the current IP address from the interface 125 * bound to the l2_packet. This is mainly for status information and the IP 126 * address will be stored as an ASCII string. This function is not essential 127 * for %wpa_supplicant operation, so full implementation is not required. 128 * l2_packet implementation will need to define the function, but it can return 129 * -1 if the IP address information is not available. 130 */ 131 int l2_packet_get_ip_addr(struct l2_packet_data *l2, char *buf, size_t len); 132 133 134 /** 135 * l2_packet_notify_auth_start - Notify l2_packet about start of authentication 136 * @l2: Pointer to internal l2_packet data from l2_packet_init() 137 * 138 * This function is called when authentication is expected to start, e.g., when 139 * association has been completed, in order to prepare l2_packet implementation 140 * for EAPOL frames. This function is used mainly if the l2_packet code needs 141 * to do polling in which case it can increasing polling frequency. This can 142 * also be an empty function if the l2_packet implementation does not benefit 143 * from knowing about the starting authentication. 144 */ 145 void l2_packet_notify_auth_start(struct l2_packet_data *l2); 146 147 /** 148 * l2_packet_set_packet_filter - Set socket filter for l2_packet 149 * @l2: Pointer to internal l2_packet data from l2_packet_init() 150 * @type: enum l2_packet_filter_type, type of filter 151 * Returns: 0 on success, -1 on failure 152 * 153 * This function is used to set the socket filter for l2_packet socket. 154 * 155 */ 156 int l2_packet_set_packet_filter(struct l2_packet_data *l2, 157 enum l2_packet_filter_type type); 158 159 #endif /* L2_PACKET_H */ 160