bsd/netinet/kpi_ipfilter.h

   1 /*
   2  * Copyright (c) 2008-2010 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
  24  * limitations under the License.
  25  *
  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_SHIFT_IFSCOPE     16
  58 #endif /* PRIVATE */
  59
  60 typedef struct ipf_pktopts *ipf_pktopts_t;
  61
  62 __BEGIN_DECLS
  63
  64 /*!
  65         @typedef ipf_input_func
  66
  67         @discussion ipf_input_func is used to filter incoming ip packets.
  68                 The IP filter is called for packets from all interfaces. The
  69                 filter is called between when the general IP processing is
  70                 handled and when the packet is passed up to the next layer
  71                 protocol such as udp or tcp. In the case of encapsulation, such
  72                 as UDP in ESP (IPSec), your filter will be called once for ESP
  73                 and then again for UDP. This will give your filter an
  74                 opportunity to process the ESP header as well as the decrypted
  75                 packet. Offset and protocol are used to determine where in the
  76                 packet processing is currently occuring. If you're only
  77                 interested in TCP or UDP packets, just return 0 if protocol
  78                 doesn't match TCP or UDP.
  79         @param cookie The cookie specified when your filter was attached.
  80         @param data The reassembled ip packet, data will start at the ip
  81                 header.
  82         @param offset An offset to the next header
  83                 (udp/tcp/icmp/esp/etc...).
  84         @param protocol The protocol type (udp/tcp/icmp/etc...) of the IP packet
  85         @result Return:
  86                 0 - The caller will continue with normal processing of the
  87                         packet.
  88                 EJUSTRETURN - The caller will stop processing the packet,
  89                         the packet will not be freed.
  90                 Anything Else - The caller will free the packet and stop
  91                         processing.
  92 */
  93 typedef errno_t (*ipf_input_func)(void *cookie, mbuf_t *data, int offset,
  94     u_int8_t protocol);
  95
  96 /*!
  97         @typedef ipf_output_func
  98
  99         @discussion ipf_output_func is used to filter outbound ip packets.
 100                 The IP filter is called for packets to all interfaces. The
 101                 filter is called before fragmentation and IPSec processing. If
 102                 you need to change the destination IP address, call
 103                 ipf_inject_output and return EJUSTRETURN.
 104         @param cookie The cookie specified when your filter was attached.
 105         @param data The ip packet, will contain an IP header followed by the
 106                 rest of the IP packet.
 107         @result Return:
 108                 0 - The caller will continue with normal processing of the
 109                         packet.
 110                 EJUSTRETURN - The caller will stop processing the packet,
 111                         the packet will not be freed.
 112                 Anything Else - The caller will free the packet and stop
 113                         processing.
 114 */
 115 typedef errno_t (*ipf_output_func)(void *cookie, mbuf_t *data,
 116     ipf_pktopts_t options);
 117
 118 /*!
 119         @typedef ipf_detach_func
 120
 121         @discussion ipf_detach_func is called to notify your filter that it
 122                 has been detached.
 123         @param cookie The cookie specified when your filter was attached.
 124 */
 125 typedef void (*ipf_detach_func)(void *cookie);
 126
 127 /*!
 128         @typedef ipf_filter
 129         @discussion This structure is used to define an IP filter for
 130                 use with the ipf_addv4 or ipf_addv6 function.
 131         @field cookie A kext defined cookie that will be passed to all
 132                 filter functions.
 133         @field name A filter name used for debugging purposes.
 134         @field ipf_input The filter function to handle inbound packets.
 135         @field ipf_output The filter function to handle outbound packets.
 136         @field ipf_detach The filter function to notify of a detach.
 137 */
 138 struct ipf_filter {
 139         void            *cookie;
 140         const char      *name;
 141         ipf_input_func  ipf_input;
 142         ipf_output_func ipf_output;
 143         ipf_detach_func ipf_detach;
 144 };
 145
 146 struct opaque_ipfilter;
 147 typedef struct opaque_ipfilter *ipfilter_t;
 148
 149 /*!
 150         @function ipf_addv4
 151         @discussion Attaches an IPv4 ip filter.
 152         @param filter A structure defining the filter.
 153         @param filter_ref A reference to the filter used to detach it.
 154         @result 0 on success otherwise the errno error.
 155  */
 156 extern errno_t ipf_addv4(const struct ipf_filter *filter,
 157     ipfilter_t *filter_ref);
 158
 159 /*!
 160         @function ipf_addv6
 161         @discussion Attaches an IPv6 ip filter.
 162         @param filter A structure defining the filter.
 163         @param filter_ref A reference to the filter used to detach it.
 164         @result 0 on success otherwise the errno error.
 165  */
 166 extern errno_t ipf_addv6(const struct ipf_filter *filter,
 167     ipfilter_t *filter_ref);
 168
 169 /*!
 170         @function ipf_remove
 171         @discussion Detaches an IPv4 or IPv6 filter.
 172         @param filter_ref The reference to the filter returned from ipf_addv4 or
 173                 ipf_addv6.
 174         @result 0 on success otherwise the errno error.
 175  */
 176 extern errno_t ipf_remove(ipfilter_t filter_ref);
 177
 178 /*!
 179         @function ipf_inject_input
 180         @discussion Inject an IP packet as though it had just been
 181                 reassembled in ip_input. When re-injecting a packet intercepted
 182                 by the filter's ipf_input function, an IP filter can pass its
 183                 reference to avoid processing the packet twice. This also
 184                 prevents ip filters installed before this filter from
 185                 getting a chance to process the packet. If the filter modified
 186                 the packet, it should not specify the filter ref to give other
 187                 filters a chance to process the new packet.
 188
 189                 Caller is responsible for freeing mbuf chain in the event that
 190                 ipf_inject_input returns an error.
 191         @param data The complete IPv4 or IPv6 packet, receive interface must
 192                 be set.
 193         @param filter_ref The reference to the filter injecting the data
 194         @result 0 on success otherwise the errno error.
 195  */
 196 extern errno_t ipf_inject_input(mbuf_t data, ipfilter_t filter_ref);
 197
 198 /*!
 199         @function ipf_inject_output
 200         @discussion Inject an IP packet as though it had just been sent to
 201                 ip_output. When re-injecting a packet intercepted by the
 202                 filter's ipf_output function, an IP filter can pass its
 203                 reference to avoid processing the packet twice. This also
 204                 prevents ip filters installed before this filter from getting a
 205                 chance to process the packet. If the filter modified the packet,
 206                 it should not specify the filter ref to give other filters a
 207                 chance to process the new packet.
 208         @param data The complete IPv4 or IPv6 packet.
 209         @param filter_ref The reference to the filter injecting the data
 210         @param options Output options for the packet
 211         @result 0 on success otherwise the errno error. ipf_inject_output
 212                 will always free the mbuf.
 213  */
 214 extern errno_t ipf_inject_output(mbuf_t data, ipfilter_t filter_ref,
 215     ipf_pktopts_t options);
 216
 217 __END_DECLS
 218 #endif /* __KPI_IPFILTER__ */