bsd/netinet/in_arp.h

   1 /*
   2  * Copyright (c) 2009-2011 Apple Inc. All rights reserved.
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * may not be used to create, or enable the creation or redistribution of,
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  13  * terms of an Apple operating system software license agreement.
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  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
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  28
  29 #ifndef _NETINET_IN_ARP_H_
  30 #define _NETINET_IN_ARP_H_
  31 #include <sys/kernel_types.h>
  32
  33 struct sockaddr;
  34 struct sockaddr_dl;
  35 struct sockaddr_in;
  36
  37 /*!
  38         @function inet_arp_lookup
  39         @discussion This function will check the routing table for a cached
  40                 arp entry or trigger an arp query to resolve the ip address to a
  41                 link-layer address.
  42
  43                 Arp entries are stored in the routing table. This function will
  44                 lookup the ip destination in the routing table. If the
  45                 destination requires forwarding to a gateway, the route of the
  46                 gateway will be looked up. The route entry is inspected to
  47                 determine if the link layer destination address is known. If
  48                 unknown, the arp generation function for IP attached to the
  49                 interface is called to create an arp request packet.
  50         @param interface The interface the packet is being sent on.
  51         @param ip_dest The ip destination of the packet.
  52         @param ll_dest On output, the link-layer destination.
  53         @param ll_dest_len The length of the buffer for ll_dest.
  54         @param hint Any routing hint passed down from the protocol.
  55         @param packet The packet being transmitted.
  56         @result May return an error such as EHOSTDOWN or ENETUNREACH. If
  57                 this function returns EJUSTRETURN, the packet has been queued
  58                 and will be sent when an arp response is received. If any other
  59                 value is returned, the caller is responsible for disposing of
  60                 the packet.
  61  */
  62 #ifdef BSD_KERNEL_PRIVATE
  63 #define inet_arp_lookup arp_lookup_ip
  64 #else
  65 extern errno_t inet_arp_lookup(ifnet_t interface,
  66     const struct sockaddr_in *ip_dest, struct sockaddr_dl *ll_dest,
  67     size_t ll_dest_len, route_t hint, mbuf_t packet);
  68 #endif /* BSD_KERNEL_PRIVATE */
  69 #ifdef KERNEL_PRIVATE
  70 struct in_addr;
  71 extern void arp_init(void);
  72 extern void in_arpdrain(void *);
  73 extern void arp_validate(struct rtentry *);
  74 extern void arp_llreach_set_reachable(struct ifnet *, void *, unsigned int);
  75 /* arp_lookup_ip is obsolete, use inet_arp_lookup */
  76 extern errno_t arp_lookup_ip(ifnet_t interface,
  77     const struct sockaddr_in *ip_dest, struct sockaddr_dl *ll_dest,
  78     size_t ll_dest_len, route_t hint, mbuf_t packet);
  79 #endif /* KERNEL_PRIVATE */
  80
  81 /*!
  82         @function inet_arp_handle_input
  83         @discussion This function should be called by code that handles
  84                 inbound arp packets. The caller should parse the ARP packet to
  85                 pull out the operation and the relevant addresses. If a response
  86                 is required, the proto_media_send_arp function will be called.
  87
  88                 This function will lookup the sender in the routing table and
  89                 add an arp entry if necessary. Any queued packets waiting for
  90                 the arp resolution will also be transmitted.
  91         @param interface The interface the packet was received on.
  92         @param arp_op The arp operation, ARPOP_REQUEST or ARPOP_REPLY
  93         @param sender_hw The sender hardware address from the arp payload.
  94         @param sender_ip The sender IP address from the arp payload.
  95         @param target_ip The target IP address from the arp payload.
  96         @result 0 on success or an errno error value on failure.
  97  */
  98 #ifdef BSD_KERNEL_PRIVATE
  99 #define inet_arp_handle_input arp_ip_handle_input
 100 #else
 101 extern errno_t inet_arp_handle_input(ifnet_t ifp, u_int16_t arpop,
 102                         const struct sockaddr_dl *sender_hw,
 103                         const struct sockaddr_in *sender_ip,
 104                         const struct sockaddr_in *target_ip);
 105 #endif /* KERNEL_PRIVATE */
 106 #ifdef KERNEL_PRIVATE
 107 /* arp_ip_handle_input is obsolete, use inet_arp_handle_input */
 108 extern errno_t arp_ip_handle_input(ifnet_t ifp, u_int16_t arpop,
 109                         const struct sockaddr_dl *sender_hw,
 110                         const struct sockaddr_in *sender_ip,
 111                         const struct sockaddr_in *target_ip);
 112 #endif /* BSD_KERNEL_PRIVATE */
 113
 114 /*!
 115         @function inet_arp_init_ifaddr
 116         @discussion This function should be called in two places, when an IP
 117                 address is added and when the hardware address changes. This
 118                 function will setup the ifaddr_t for use with the IP ARP
 119                 functions. This function will also trigger the transmission of a
 120                 gratuitous ARP packet.
 121
 122                 When the SIOCSIFADDR ioctl is handled, the data parameter will
 123                 be an ifaddr_t. If this is an IP address, inet_arp_init_ifaddr
 124                 should be called. This is usually performed in the protocol
 125                 attachment's ioctl handler.
 126
 127                 When the event handler for the protocol attachment receives a
 128                 KEV_DL_LINK_ADDRESS_CHANGED event, the event handler should call
 129                 inet_arp_init_ifaddr for each interface ip address.
 130
 131                 For an example, see bsd/net/ether_inet_pr_module.c in xnu.
 132                 Search for inet_arp_init_ifaddr.
 133         @param interface The interface the packet was received on.
 134         @param ipaddr The ip interface address.
 135  */
 136 #ifdef BSD_KERNEL_PRIVATE
 137 /* inet_arp_init_ifaddr is aliased to arp_ifinit */
 138 #define inet_arp_init_ifaddr    arp_ifinit
 139 #else
 140 extern void inet_arp_init_ifaddr(ifnet_t interface, ifaddr_t ipaddr);
 141 #endif
 142
 143 #endif /* _NETINET_IN_ARP_H_ */