bsd/netinet/kpi_ipfilter.h

   1 /*
   2  * Copyright (c) 2003-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*!
  31         @header kpi_ipfilter.h
  32         This header defines an API to attach IP filters. IP filters may be
  33         attached to intercept either IPv4 or IPv6 packets. The filters can
  34         intercept all IP packets in to and out of the host regardless of
  35         interface.
  36  */
  37
  38 #ifndef __KPI_IPFILTER__
  39 #define __KPI_IPFILTER__
  40
  41 #include <sys/kernel_types.h>
  42
  43 /*
  44  * ipf_pktopts
  45  *
  46  * Options for outgoing packets. The options need to be preserved when
  47  * re-injecting a packet.
  48  */
  49 struct ipf_pktopts {
  50         u_int32_t                       ippo_flags;
  51         ifnet_t                         ippo_mcast_ifnet;
  52         int                                     ippo_mcast_loop;
  53         u_int8_t                        ippo_mcast_ttl;
  54 };
  55 #define IPPOF_MCAST_OPTS 0x1
  56
  57 typedef struct ipf_pktopts* ipf_pktopts_t;
  58
  59 /*!
  60         @typedef ipf_input_func
  61
  62         @discussion ipf_input_func is used to filter incoming ip packets.
  63                 The IP filter is called for packets from all interfaces. The
  64                 filter is called between when the general IP processing is
  65                 handled and when the packet is passed up to the next layer
  66                 protocol such as udp or tcp. In the case of encapsulation, such
  67                 as UDP in ESP (IPSec), your filter will be called once for ESP
  68                 and then again for UDP. This will give your filter an
  69                 opportunity to process the ESP header as well as the decrypted
  70                 packet. Offset and protocol are used to determine where in the
  71                 packet processing is currently occuring. If you're only
  72                 interested in TCP or UDP packets, just return 0 if protocol
  73                 doesn't match TCP or UDP.
  74         @param cookie The cookie specified when your filter was attached.
  75         @param data The reassembled ip packet, data will start at the ip
  76                 header.
  77         @param offset An offset to the next header
  78                 (udp/tcp/icmp/esp/etc...).
  79         @param protocol The protocol type (udp/tcp/icmp/etc...) of the IP packet
  80         @result Return:
  81                 0 - The caller will continue with normal processing of the packet.
  82                 EJUSTRETURN - The caller will stop processing the packet, the packet will not be freed.
  83                 Anything Else - The caller will free the packet and stop processing.
  84 */
  85 typedef errno_t (*ipf_input_func)(void* cookie, mbuf_t *data, int offset, u_int8_t protocol);
  86
  87 /*!
  88         @typedef ipf_output_func
  89
  90         @discussion ipf_output_func is used to filter outbound ip packets.
  91                 The IP filter is called for packets to all interfaces. The
  92                 filter is called before fragmentation and IPSec processing. If
  93                 you need to change the destination IP address, call
  94                 ipf_inject_output and return EJUSTRETURN.
  95         @param cookie The cookie specified when your filter was attached.
  96         @param data The ip packet, will contain an IP header followed by the
  97                 rest of the IP packet.
  98         @result Return:
  99                 0 - The caller will continue with normal processing of the packet.
 100                 EJUSTRETURN - The caller will stop processing the packet, the packet will not be freed.
 101                 Anything Else - The caller will free the packet and stop processing.
 102 */
 103 typedef errno_t (*ipf_output_func)(void* cookie, mbuf_t *data, ipf_pktopts_t options);
 104
 105 /*!
 106         @typedef ipf_detach_func
 107
 108         @discussion ipf_detach_func is called to notify your filter that it
 109                 has been detached.
 110         @param cookie The cookie specified when your filter was attached.
 111 */
 112 typedef void (*ipf_detach_func)(void* cookie);
 113
 114 /*!
 115         @typedef ipf_filter
 116         @discussion This structure is used to define an IP filter for
 117                 use with the ipf_addv4 or ipf_addv6 function.
 118         @field cookie A kext defined cookie that will be passed to all
 119                 filter functions.
 120         @field name A filter name used for debugging purposes.
 121         @field ipf_input The filter function to handle inbound packets.
 122         @field ipf_output The filter function to handle outbound packets.
 123         @field ipf_detach The filter function to notify of a detach.
 124 */
 125 struct ipf_filter {
 126         void*           cookie;
 127         const char*     name;
 128         ipf_input_func  ipf_input;
 129         ipf_output_func ipf_output;
 130         ipf_detach_func ipf_detach;
 131 };
 132
 133 struct opaque_ipfilter;
 134 typedef struct opaque_ipfilter* ipfilter_t;
 135
 136 /*!
 137         @function ipf_addv4
 138         @discussion Attaches an IPv4 ip filter.
 139         @param filter A structure defining the filter.
 140         @param filter_ref A reference to the filter used to detach it.
 141         @result 0 on success otherwise the errno error.
 142  */
 143 errno_t ipf_addv4(const struct ipf_filter* filter, ipfilter_t *filter_ref);
 144
 145 /*!
 146         @function ipf_addv6
 147         @discussion Attaches an IPv6 ip filter.
 148         @param filter A structure defining the filter.
 149         @param filter_ref A reference to the filter used to detach it.
 150         @result 0 on success otherwise the errno error.
 151  */
 152 errno_t ipf_addv6(const struct ipf_filter* filter, ipfilter_t *filter_ref);
 153
 154 /*!
 155         @function ipf_remove
 156         @discussion Detaches an IPv4 or IPv6 filter.
 157         @param filter_ref The reference to the filter returned from ipf_addv4 or
 158                 ipf_addv6.
 159         @result 0 on success otherwise the errno error.
 160  */
 161 errno_t ipf_remove(ipfilter_t filter_ref);
 162
 163 /*!
 164         @function ipf_inject_input
 165         @discussion Inject an IP packet as though it had just been
 166                 reassembled in ip_input. When re-injecting a packet intercepted
 167                 by the filter's ipf_input function, an IP filter can pass its
 168                 reference to avoid processing the packet twice. This also
 169                 prevents ip filters installed before this filter from
 170                 getting a chance to process the packet. If the filter modified
 171                 the packet, it should not specify the filter ref to give other
 172                 filters a chance to process the new packet.
 173
 174                 Caller is responsible for freeing mbuf chain in the event that
 175                 ipf_inject_input returns an error.
 176         @param data The complete IPv4 or IPv6 packet, receive interface must
 177                 be set.
 178         @param filter_ref The reference to the filter injecting the data
 179         @result 0 on success otherwise the errno error.
 180  */
 181 errno_t ipf_inject_input(mbuf_t data, ipfilter_t filter_ref);
 182
 183 /*!
 184         @function ipf_inject_output
 185         @discussion Inject an IP packet as though it had just been sent to
 186                 ip_output. When re-injecting a packet intercepted by the
 187                 filter's ipf_output function, an IP filter can pass its
 188                 reference to avoid processing the packet twice. This also
 189                 prevents ip filters installed before this filter from getting a
 190                 chance to process the packet. If the filter modified the packet,
 191                 it should not specify the filter ref to give other filters a
 192                 chance to process the new packet.
 193         @param data The complete IPv4 or IPv6 packet.
 194         @param filter_ref The reference to the filter injecting the data
 195         @param options Output options for the packet
 196         @result 0 on success otherwise the errno error. ipf_inject_output
 197                 will always free the mbuf.
 198  */
 199 errno_t ipf_inject_output(mbuf_t data, ipfilter_t filter_ref, ipf_pktopts_t options);
 200
 201 #endif /* __KPI_IPFILTER__ */