1/* 2 * Copyright (c) 2008-2014 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, 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_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 */ 47struct 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 63typedef 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*/ 96typedef 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*/ 118typedef 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*/ 128typedef 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*/ 141struct 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 149struct opaque_ipfilter; 150typedef 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 */ 159extern errno_t ipf_addv4(const struct ipf_filter *filter, 160 ipfilter_t *filter_ref); 161 162/*! 163 @function ipf_addv6 164 @discussion Attaches an IPv6 ip filter. 165 @param filter A structure defining the filter. 166 @param filter_ref A reference to the filter used to detach it. 167 @result 0 on success otherwise the errno error. 168 */ 169extern errno_t ipf_addv6(const struct ipf_filter *filter, 170 ipfilter_t *filter_ref); 171 172/*! 173 @function ipf_remove 174 @discussion Detaches an IPv4 or IPv6 filter. 175 @param filter_ref The reference to the filter returned from ipf_addv4 or 176 ipf_addv6. 177 @result 0 on success otherwise the errno error. 178 */ 179extern errno_t ipf_remove(ipfilter_t filter_ref); 180 181/*! 182 @function ipf_inject_input 183 @discussion Inject an IP packet as though it had just been 184 reassembled in ip_input. When re-injecting a packet intercepted 185 by the filter's ipf_input function, an IP filter can pass its 186 reference to avoid processing the packet twice. This also 187 prevents ip filters installed before this filter from 188 getting a chance to process the packet. If the filter modified 189 the packet, it should not specify the filter ref to give other 190 filters a chance to process the new packet. 191 192 Caller is responsible for freeing mbuf chain in the event that 193 ipf_inject_input returns an error. 194 @param data The complete IPv4 or IPv6 packet, receive interface must 195 be set. 196 @param filter_ref The reference to the filter injecting the data 197 @result 0 on success otherwise the errno error. 198 */ 199extern errno_t ipf_inject_input(mbuf_t data, ipfilter_t filter_ref); 200 201/*! 202 @function ipf_inject_output 203 @discussion Inject an IP packet as though it had just been sent to 204 ip_output. When re-injecting a packet intercepted by the 205 filter's ipf_output function, an IP filter can pass its 206 reference to avoid processing the packet twice. This also 207 prevents ip filters installed before this filter from getting a 208 chance to process the packet. If the filter modified the packet, 209 it should not specify the filter ref to give other filters a 210 chance to process the new packet. 211 @param data The complete IPv4 or IPv6 packet. 212 @param filter_ref The reference to the filter injecting the data 213 @param options Output options for the packet 214 @result 0 on success otherwise the errno error. ipf_inject_output 215 will always free the mbuf. 216 */ 217extern errno_t ipf_inject_output(mbuf_t data, ipfilter_t filter_ref, 218 ipf_pktopts_t options); 219 220__END_DECLS 221#endif /* __KPI_IPFILTER__ */ 222