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1 /**
2  * @file
3  *
4  * AutoIP Automatic LinkLocal IP Configuration
5  */
6 
7 /*
8  *
9  * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without modification,
13  * are permitted provided that the following conditions are met:
14  *
15  * 1. Redistributions of source code must retain the above copyright notice,
16  *    this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright notice,
18  *    this list of conditions and the following disclaimer in the documentation
19  *    and/or other materials provided with the distribution.
20  * 3. The name of the author may not be used to endorse or promote products
21  *    derived from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
24  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
26  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
27  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
28  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
31  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
32  * OF SUCH DAMAGE.
33  *
34  * Author: Dominik Spies <kontakt@dspies.de>
35  *
36  * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
37  * with RFC 3927.
38  *
39  *
40  * Please coordinate changes and requests with Dominik Spies
41  * <kontakt@dspies.de>
42  */
43 
44 #ifndef __LWIP_AUTOIP_H__
45 #define __LWIP_AUTOIP_H__
46 
47 #include "lwip/opt.h"
48 
49 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
50 
51 #include "lwip/netif.h"
52 #include "lwip/udp.h"
53 #include "netif/etharp.h"
54 
55 #ifdef __cplusplus
56 extern "C" {
57 #endif
58 
59 /* AutoIP Timing */
60 #define AUTOIP_TMR_INTERVAL      100
61 #define AUTOIP_TICKS_PER_SECOND (1000 / AUTOIP_TMR_INTERVAL)
62 
63 /* RFC 3927 Constants */
64 #define PROBE_WAIT               1   /* second   (initial random delay)                 */
65 #define PROBE_MIN                1   /* second   (minimum delay till repeated probe)    */
66 #define PROBE_MAX                2   /* seconds  (maximum delay till repeated probe)    */
67 #define PROBE_NUM                3   /*          (number of probe packets)              */
68 #define ANNOUNCE_NUM             2   /*          (number of announcement packets)       */
69 #define ANNOUNCE_INTERVAL        2   /* seconds  (time between announcement packets)    */
70 #define ANNOUNCE_WAIT            2   /* seconds  (delay before announcing)              */
71 #define MAX_CONFLICTS            10  /*          (max conflicts before rate limiting)   */
72 #define RATE_LIMIT_INTERVAL      60  /* seconds  (delay between successive attempts)    */
73 #define DEFEND_INTERVAL          10  /* seconds  (min. wait between defensive ARPs)     */
74 
75 /* AutoIP client states */
76 #define AUTOIP_STATE_OFF         0
77 #define AUTOIP_STATE_PROBING     1
78 #define AUTOIP_STATE_ANNOUNCING  2
79 #define AUTOIP_STATE_BOUND       3
80 
81 struct autoip
82 {
83   ip_addr_t llipaddr;       /* the currently selected, probed, announced or used LL IP-Address */
84   u8_t state;               /* current AutoIP state machine state */
85   u8_t sent_num;            /* sent number of probes or announces, dependent on state */
86   u16_t ttw;                /* ticks to wait, tick is AUTOIP_TMR_INTERVAL long */
87   u8_t lastconflict;        /* ticks until a conflict can be solved by defending */
88   u8_t tried_llipaddr;      /* total number of probed/used Link Local IP-Addresses */
89 };
90 
91 
92 /** Init srand, has to be called before entering mainloop */
93 void autoip_init(void);
94 
95 /** Set a struct autoip allocated by the application to work with */
96 void autoip_set_struct(struct netif *netif, struct autoip *autoip);
97 
98 /** Start AutoIP client */
99 err_t autoip_start(struct netif *netif);
100 
101 /** Stop AutoIP client */
102 err_t autoip_stop(struct netif *netif);
103 
104 /** Handles every incoming ARP Packet, called by etharp_arp_input */
105 void autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr);
106 
107 /** Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds */
108 void autoip_tmr(void);
109 
110 /** Handle a possible change in the network configuration */
111 void autoip_network_changed(struct netif *netif);
112 
113 #ifdef __cplusplus
114 }
115 #endif
116 
117 #endif /* LWIP_AUTOIP */
118 
119 #endif /* __LWIP_AUTOIP_H__ */
120