bsd/net/kpi_interfacefilter.h

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*!
  29         @header kpi_interfacefilter.h
  30         This header defines an API to attach interface filters. Interface
  31         filters may be attached to a specific interface. The filters can
  32         intercept all packets in to and out of the specific interface. In
  33         addition, the filters may intercept interface specific events and
  34         ioctls.
  35  */
  36
  37 #ifndef __KPI_INTERFACEFILTER__
  38 #define __KPI_INTERFACEFILTER__
  39 #include <sys/kernel_types.h>
  40 #include <net/kpi_interface.h>
  41
  42 struct kev_msg;
  43
  44 __BEGIN_DECLS
  45
  46 /*!
  47         @typedef iff_input_func
  48
  49         @discussion iff_input_func is used to filter incoming packets. The
  50                 interface is only valid for the duration of the filter call. If
  51                 you need to keep a reference to the interface, be sure to call
  52                 ifnet_reference and ifnet_release. The packets passed to the
  53                 inbound filter are different from those passed to the outbound
  54                 filter. Packets to the inbound filter have the frame header
  55                 passed in separately from the rest of the packet. The outbound
  56                 data filters is passed the whole packet including the frame
  57                 header.
  58
  59                 The frame header usually preceeds the data in the mbuf. This
  60                 ensures that the frame header will be a valid pointer as long as
  61                 the mbuf is not freed. If you need to change the frame header to
  62                 point somewhere else, the recommended method is to prepend a new
  63                 frame header to the mbuf chain (mbuf_prepend), set the header to
  64                 point to that data, then call mbuf_adj to move the mbuf data
  65                 pointer back to the start of the packet payload.
  66         @param cookie The cookie specified when this filter was attached.
  67         @param interface The interface the packet was recieved on.
  68         @param protocol The protocol of this packet. If you specified a
  69                 protocol when attaching your filter, the protocol will only ever
  70                 be the protocol you specified.
  71         @param data The inbound packet, after the frame header as determined
  72                 by the interface.
  73         @param frame_ptr A pointer to the pointer to the frame header. The
  74                 frame header length can be found by inspecting the interface's
  75                 frame header length (ifnet_hdrlen).
  76         @result Return:
  77                 0 - The caller will continue with normal processing of the packet.
  78                 EJUSTRETURN - The caller will stop processing the packet, the packet will not be freed.
  79                 Anything Else - The caller will free the packet and stop processing.
  80 */
  81 typedef errno_t (*iff_input_func)(void* cookie, ifnet_t interface, protocol_family_t protocol,
  82                                                                   mbuf_t *data, char **frame_ptr);
  83
  84 /*!
  85         @typedef iff_output_func
  86
  87         @discussion iff_output_func is used to filter fully formed outbound
  88                 packets. The interface is only valid for the duration of the
  89                 filter call. If you need to keep a reference to the interface,
  90                 be sure to call ifnet_reference and ifnet_release.
  91         @param cookie The cookie specified when this filter was attached.
  92         @param interface The interface the packet is being transmitted on.
  93         @param data The fully formed outbound packet in a chain of mbufs.
  94                 The frame header is already included. The filter function may
  95                 modify the packet or return a different mbuf chain.
  96         @result Return:
  97                 0 - The caller will continue with normal processing of the packet.
  98                 EJUSTRETURN - The caller will stop processing the packet, the packet will not be freed.
  99                 Anything Else - The caller will free the packet and stop processing.
 100 */
 101 typedef errno_t (*iff_output_func)(void* cookie, ifnet_t interface, protocol_family_t protocol,
 102                                                                    mbuf_t *data);
 103
 104 /*!
 105         @typedef iff_event_func
 106
 107         @discussion iff_event_func is used to filter interface specific
 108                 events. The interface is only valid for the duration of the
 109                 filter call. If you need to keep a reference to the interface,
 110                 be sure to call ifnet_reference and ifnet_release.
 111         @param cookie The cookie specified when this filter was attached.
 112         @param interface The interface the packet is being transmitted on.
 113         @param event_msg The kernel event, may not be changed.
 114 */
 115 typedef void (*iff_event_func)(void* cookie, ifnet_t interface, protocol_family_t protocol,
 116                                                            const struct kev_msg *event_msg);
 117
 118 /*!
 119         @typedef iff_ioctl_func
 120
 121         @discussion iff_ioctl_func is used to filter ioctls sent to an
 122                 interface. The interface is only valid for the duration of the
 123                 filter call. If you need to keep a reference to the interface,
 124                 be sure to call ifnet_reference and ifnet_release.
 125
 126                 All undefined ioctls are reserved for future use by Apple. If
 127                 you need to communicate with your kext using an ioctl, please
 128                 use SIOCSIFKPI and SIOCGIFKPI.
 129         @param cookie The cookie specified when this filter was attached.
 130         @param interface The interface the packet is being transmitted on.
 131         @param ioctl_cmd The ioctl command.
 132         @param ioctl_arg A pointer to the ioctl argument.
 133         @result Return:
 134                 0 - This filter function handled the ioctl.
 135                 EOPNOTSUPP - This filter function does not understand/did not handle this ioctl.
 136                 EJUSTRETURN - This filter function handled the ioctl, processing should stop.
 137                 Anything Else - Processing will stop, the error will be returned.
 138 */
 139 typedef errno_t (*iff_ioctl_func)(void* cookie, ifnet_t interface, protocol_family_t protocol,
 140                                                                   u_long ioctl_cmd, void* ioctl_arg);
 141
 142 /*!
 143         @typedef iff_detached_func
 144
 145         @discussion iff_detached_func is called to notify the filter that it
 146                 has been detached from an interface. This is the last call to
 147                 the filter that will be made. A filter may be detached if the
 148                 interface is detached or the detach filter function is called.
 149                 In the case that the interface is being detached, your filter's
 150                 event function will be called with the interface detaching event
 151                 before the your detached function will be called.
 152         @param cookie The cookie specified when this filter was attached.
 153         @param interface The interface this filter was detached from.
 154 */
 155 typedef void (*iff_detached_func)(void* cookie, ifnet_t interface);
 156
 157 /*!
 158         @struct iff_filter
 159         @discussion This structure is used to define an interface filter for
 160                 use with the iflt_attach function.
 161         @field iff_cookie A kext defined cookie that will be passed to all
 162                 filter functions.
 163         @field iff_name A filter name used for debugging purposes.
 164         @field iff_protocol The protocol of the packets this filter is
 165                 interested in. If you specify zero, packets from all protocols
 166                 will be passed to the filter.
 167         @field iff_input The filter function to handle inbound packets, may
 168                 be NULL.
 169         @field iff_output The filter function to handle outbound packets,
 170                 may be NULL.
 171         @field iff_event The filter function to handle interface events, may
 172                 be null.
 173         @field iff_ioctl The filter function to handle interface ioctls, may
 174                 be null.
 175         @field iff_detached The filter function used to notify the filter that
 176                 it has been detached.
 177 */
 178
 179 struct iff_filter {
 180         void*                           iff_cookie;
 181         const char*                     iff_name;
 182         protocol_family_t       iff_protocol;
 183         iff_input_func          iff_input;
 184         iff_output_func         iff_output;
 185         iff_event_func          iff_event;
 186         iff_ioctl_func          iff_ioctl;
 187         iff_detached_func       iff_detached;
 188 };
 189
 190 /*!
 191         @function iflt_attach
 192         @discussion Attaches an interface filter to an interface.
 193         @param interface The interface the filter should be attached to.
 194         @param filter A structure defining the filter.
 195         @param filter_ref A reference to the filter used to detach.
 196         @result 0 on success otherwise the errno error.
 197  */
 198 errno_t iflt_attach(ifnet_t interface, const struct iff_filter* filter,
 199                                     interface_filter_t *filter_ref);
 200
 201 /*!
 202         @function iflt_detach
 203         @discussion Detaches an interface filter from an interface.
 204         @param filter_ref The reference to the filter from iflt_attach.
 205  */
 206 void iflt_detach(interface_filter_t filter_ref);
 207
 208 __END_DECLS
 209 #endif