bsd/netinet/kpi_ipfilter.h

   1 /*
   2  * Copyright (c) 2008-2017 Apple 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,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*!
  29         @header kpi_ipfilter.h
  30         This header defines an API to attach IP filters. IP filters may be
  31         attached to intercept either IPv4 or IPv6 packets. The filters can
  32         intercept all IP packets in to and out of the host regardless of
  33         interface.
  34  */
  35
  36 #ifndef __KPI_IPFILTER__
  37 #define __KPI_IPFILTER__
  38
  39 #include <sys/kernel_types.h>
  40
  41 /*
  42  * ipf_pktopts
  43  *
  44  * Options for outgoing packets. The options need to be preserved when
  45  * re-injecting a packet.
  46  */
  47 struct ipf_pktopts {
  48         u_int32_t                       ippo_flags;
  49         ifnet_t                         ippo_mcast_ifnet;
  50         int                             ippo_mcast_loop;
  51         u_int8_t                        ippo_mcast_ttl;
  52 };
  53 #define IPPOF_MCAST_OPTS        0x1
  54 #ifdef PRIVATE
  55 #define IPPOF_BOUND_IF          0x2
  56 #define IPPOF_NO_IFT_CELLULAR   0x4
  57 #define IPPOF_SELECT_SRCIF      0x8
  58 #define IPPOF_BOUND_SRCADDR     0x10
  59 #define IPPOF_SHIFT_IFSCOPE     16
  60 #define IPPOF_NO_IFF_EXPENSIVE  0x20
  61 #endif /* PRIVATE */
  62
  63 typedef struct ipf_pktopts *ipf_pktopts_t;
  64
  65 __BEGIN_DECLS
  66
  67 /*!
  68         @typedef ipf_input_func
  69
  70         @discussion ipf_input_func is used to filter incoming ip packets.
  71                 The IP filter is called for packets from all interfaces. The
  72                 filter is called between when the general IP processing is
  73                 handled and when the packet is passed up to the next layer
  74                 protocol such as udp or tcp. In the case of encapsulation, such
  75                 as UDP in ESP (IPSec), your filter will be called once for ESP
  76                 and then again for UDP. This will give your filter an
  77                 opportunity to process the ESP header as well as the decrypted
  78                 packet. Offset and protocol are used to determine where in the
  79                 packet processing is currently occuring. If you're only
  80                 interested in TCP or UDP packets, just return 0 if protocol
  81                 doesn't match TCP or UDP.
  82         @param cookie The cookie specified when your filter was attached.
  83         @param data The reassembled ip packet, data will start at the ip
  84                 header.
  85         @param offset An offset to the next header
  86                 (udp/tcp/icmp/esp/etc...).
  87         @param protocol The protocol type (udp/tcp/icmp/etc...) of the IP packet
  88         @result Return:
  89                 0 - The caller will continue with normal processing of the
  90                         packet.
  91                 EJUSTRETURN - The caller will stop processing the packet,
  92                         the packet will not be freed.
  93                 Anything Else - The caller will free the packet and stop
  94                         processing.
  95 */
  96 typedef errno_t (*ipf_input_func)(void *cookie, mbuf_t *data, int offset,
  97     u_int8_t protocol);
  98
  99 /*!
 100         @typedef ipf_output_func
 101
 102         @discussion ipf_output_func is used to filter outbound ip packets.
 103                 The IP filter is called for packets to all interfaces. The
 104                 filter is called before fragmentation and IPSec processing. If
 105                 you need to change the destination IP address, call
 106                 ipf_inject_output and return EJUSTRETURN.
 107         @param cookie The cookie specified when your filter was attached.
 108         @param data The ip packet, will contain an IP header followed by the
 109                 rest of the IP packet.
 110         @result Return:
 111                 0 - The caller will continue with normal processing of the
 112                         packet.
 113                 EJUSTRETURN - The caller will stop processing the packet,
 114                         the packet will not be freed.
 115                 Anything Else - The caller will free the packet and stop
 116                         processing.
 117 */
 118 typedef errno_t (*ipf_output_func)(void *cookie, mbuf_t *data,
 119     ipf_pktopts_t options);
 120
 121 /*!
 122         @typedef ipf_detach_func
 123
 124         @discussion ipf_detach_func is called to notify your filter that it
 125                 has been detached.
 126         @param cookie The cookie specified when your filter was attached.
 127 */
 128 typedef void (*ipf_detach_func)(void *cookie);
 129
 130 /*!
 131         @typedef ipf_filter
 132         @discussion This structure is used to define an IP filter for
 133                 use with the ipf_addv4 or ipf_addv6 function.
 134         @field cookie A kext defined cookie that will be passed to all
 135                 filter functions.
 136         @field name A filter name used for debugging purposes.
 137         @field ipf_input The filter function to handle inbound packets.
 138         @field ipf_output The filter function to handle outbound packets.
 139         @field ipf_detach The filter function to notify of a detach.
 140 */
 141 struct ipf_filter {
 142         void            *cookie;
 143         const char      *name;
 144         ipf_input_func  ipf_input;
 145         ipf_output_func ipf_output;
 146         ipf_detach_func ipf_detach;
 147 };
 148
 149 struct opaque_ipfilter;
 150 typedef struct opaque_ipfilter *ipfilter_t;
 151
 152 /*!
 153         @function ipf_addv4
 154         @discussion Attaches an IPv4 ip filter.
 155         @param filter A structure defining the filter.
 156         @param filter_ref A reference to the filter used to detach it.
 157         @result 0 on success otherwise the errno error.
 158  */
 159 #ifdef KERNEL_PRIVATE
 160 extern errno_t ipf_addv4_internal(const struct ipf_filter *filter,
 161     ipfilter_t *filter_ref);
 162
 163 #define ipf_addv4(filter, filter_ref) \
 164     ipf_addv4_internal((filter), (filter_ref))
 165 #else
 166 extern errno_t ipf_addv4(const struct ipf_filter *filter,
 167     ipfilter_t *filter_ref);
 168 #endif /* KERNEL_PRIVATE */
 169
 170 /*!
 171         @function ipf_addv6
 172         @discussion Attaches an IPv6 ip filter.
 173         @param filter A structure defining the filter.
 174         @param filter_ref A reference to the filter used to detach it.
 175         @result 0 on success otherwise the errno error.
 176  */
 177 #ifdef KERNEL_PRIVATE
 178 extern errno_t ipf_addv6_internal(const struct ipf_filter *filter,
 179     ipfilter_t *filter_ref);
 180
 181 #define ipf_addv6(filter, filter_ref) \
 182     ipf_addv6_internal((filter), (filter_ref))
 183 #else
 184 extern errno_t ipf_addv6(const struct ipf_filter *filter,
 185     ipfilter_t *filter_ref);
 186 #endif /* KERNEL_PRIVATE */
 187
 188 /*!
 189         @function ipf_remove
 190         @discussion Detaches an IPv4 or IPv6 filter.
 191         @param filter_ref The reference to the filter returned from ipf_addv4 or
 192                 ipf_addv6.
 193         @result 0 on success otherwise the errno error.
 194  */
 195 extern errno_t ipf_remove(ipfilter_t filter_ref);
 196
 197 /*!
 198         @function ipf_inject_input
 199         @discussion Inject an IP packet as though it had just been
 200                 reassembled in ip_input. When re-injecting a packet intercepted
 201                 by the filter's ipf_input function, an IP filter can pass its
 202                 reference to avoid processing the packet twice. This also
 203                 prevents ip filters installed before this filter from
 204                 getting a chance to process the packet. If the filter modified
 205                 the packet, it should not specify the filter ref to give other
 206                 filters a chance to process the new packet.
 207
 208                 Caller is responsible for freeing mbuf chain in the event that
 209                 ipf_inject_input returns an error.
 210         @param data The complete IPv4 or IPv6 packet, receive interface must
 211                 be set.
 212         @param filter_ref The reference to the filter injecting the data
 213         @result 0 on success otherwise the errno error.
 214  */
 215 extern errno_t ipf_inject_input(mbuf_t data, ipfilter_t filter_ref);
 216
 217 /*!
 218         @function ipf_inject_output
 219         @discussion Inject an IP packet as though it had just been sent to
 220                 ip_output. When re-injecting a packet intercepted by the
 221                 filter's ipf_output function, an IP filter can pass its
 222                 reference to avoid processing the packet twice. This also
 223                 prevents ip filters installed before this filter from getting a
 224                 chance to process the packet. If the filter modified the packet,
 225                 it should not specify the filter ref to give other filters a
 226                 chance to process the new packet.
 227         @param data The complete IPv4 or IPv6 packet.
 228         @param filter_ref The reference to the filter injecting the data
 229         @param options Output options for the packet
 230         @result 0 on success otherwise the errno error. ipf_inject_output
 231                 will always free the mbuf.
 232  */
 233 extern errno_t ipf_inject_output(mbuf_t data, ipfilter_t filter_ref,
 234     ipf_pktopts_t options);
 235
 236 __END_DECLS
 237 #endif /* __KPI_IPFILTER__ */