/** | |
* @file | |
* AutoIP Automatic LinkLocal IP Configuration | |
* | |
*/ | |
/* | |
* | |
* Copyright (c) 2007 Dominik Spies <kontakt@dspies.de> | |
* All rights reserved. | |
* | |
* Redistribution and use in source and binary forms, with or without modification, | |
* are permitted provided that the following conditions are met: | |
* | |
* 1. Redistributions of source code must retain the above copyright notice, | |
* this list of conditions and the following disclaimer. | |
* 2. Redistributions in binary form must reproduce the above copyright notice, | |
* this list of conditions and the following disclaimer in the documentation | |
* and/or other materials provided with the distribution. | |
* 3. The name of the author may not be used to endorse or promote products | |
* derived from this software without specific prior written permission. | |
* | |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT | |
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT | |
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING | |
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY | |
* OF SUCH DAMAGE. | |
* | |
* Author: Dominik Spies <kontakt@dspies.de> | |
* | |
* This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform | |
* with RFC 3927. | |
* | |
* | |
* Please coordinate changes and requests with Dominik Spies | |
* <kontakt@dspies.de> | |
*/ | |
/******************************************************************************* | |
* USAGE: | |
* | |
* define LWIP_AUTOIP 1 in your lwipopts.h | |
* | |
* If you don't use tcpip.c (so, don't call, you don't call tcpip_init): | |
* - First, call autoip_init(). | |
* - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces, | |
* that should be defined in autoip.h. | |
* I recommend a value of 100. The value must divide 1000 with a remainder almost 0. | |
* Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 .... | |
* | |
* Without DHCP: | |
* - Call autoip_start() after netif_add(). | |
* | |
* With DHCP: | |
* - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h. | |
* - Configure your DHCP Client. | |
* | |
*/ | |
#include "lwip/opt.h" | |
#if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */ | |
#include "lwip/mem.h" | |
#include "lwip/udp.h" | |
#include "lwip/ip_addr.h" | |
#include "lwip/netif.h" | |
#include "lwip/autoip.h" | |
#include "netif/etharp.h" | |
#include <stdlib.h> | |
#include <string.h> | |
/* Pseudo random macro based on netif informations. | |
* You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */ | |
#ifndef LWIP_AUTOIP_RAND | |
#define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \ | |
((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \ | |
((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \ | |
((u32_t)((netif->hwaddr[4]) & 0xff))) + \ | |
(netif->autoip?netif->autoip->tried_llipaddr:0)) | |
#endif /* LWIP_AUTOIP_RAND */ | |
/* static functions */ | |
static void autoip_handle_arp_conflict(struct netif *netif); | |
/* creates random LL IP-Address for a network interface */ | |
static void autoip_create_rand_addr(struct netif *netif, struct ip_addr *RandomIPAddr); | |
/* sends an ARP announce */ | |
static err_t autoip_arp_announce(struct netif *netif); | |
/* configure interface for use with current LL IP-Address */ | |
static err_t autoip_bind(struct netif *netif); | |
/** | |
* Initialize this module | |
*/ | |
void | |
autoip_init(void) | |
{ | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_init()\n")); | |
} | |
/** | |
* Handle a IP address conflict after an ARP conflict detection | |
*/ | |
static void | |
autoip_handle_arp_conflict(struct netif *netif) | |
{ | |
/* Somehow detect if we are defending or retreating */ | |
unsigned char defend = 1; /* tbd */ | |
if(defend) { | |
if(netif->autoip->lastconflict > 0) { | |
/* retreat, there was a conflicting ARP in the last | |
* DEFEND_INTERVAL seconds | |
*/ | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n")); | |
/* TODO: close all TCP sessions */ | |
autoip_start(netif); | |
} else { | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n")); | |
autoip_arp_announce(netif); | |
netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND; | |
} | |
} else { | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_handle_arp_conflict(): we do not defend, retreating\n")); | |
/* TODO: close all TCP sessions */ | |
autoip_start(netif); | |
} | |
} | |
/** | |
* Create an IP-Address out of range 169.254.1.0 to 169.254.254.255 | |
* | |
* @param netif network interface on which create the IP-Address | |
* @param RandomIPAddr ip address to initialize | |
*/ | |
static void | |
autoip_create_rand_addr(struct netif *netif, struct ip_addr *RandomIPAddr) | |
{ | |
/* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255 | |
* compliant to RFC 3927 Section 2.1 | |
* We have 254 * 256 possibilities | |
*/ | |
RandomIPAddr->addr = (0xA9FE0100 + ((u32_t)(((u8_t)(netif->hwaddr[4])) | | |
((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)) + netif->autoip->tried_llipaddr); | |
if (RandomIPAddr->addr>0xA9FEFEFF) { | |
RandomIPAddr->addr = (0xA9FE0100 + (RandomIPAddr->addr-0xA9FEFEFF)); | |
} | |
if (RandomIPAddr->addr<0xA9FE0100) { | |
RandomIPAddr->addr = (0xA9FEFEFF - (0xA9FE0100-RandomIPAddr->addr)); | |
} | |
RandomIPAddr->addr = htonl(RandomIPAddr->addr); | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_create_rand_addr(): tried_llipaddr=%"U16_F", 0x%08"X32_F"\n", | |
(u16_t)(netif->autoip->tried_llipaddr), (u32_t)(RandomIPAddr->addr))); | |
} | |
/** | |
* Sends an ARP announce from a network interface | |
* | |
* @param netif network interface used to send the announce | |
*/ | |
static err_t | |
autoip_arp_announce(struct netif *netif) | |
{ | |
return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, | |
(struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, ðzero, | |
&netif->autoip->llipaddr, ARP_REQUEST); | |
} | |
/** | |
* Configure interface for use with current LL IP-Address | |
* | |
* @param netif network interface to configure with current LL IP-Address | |
*/ | |
static err_t | |
autoip_bind(struct netif *netif) | |
{ | |
struct autoip *autoip = netif->autoip; | |
struct ip_addr sn_mask, gw_addr; | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, | |
("autoip_bind(netif=%p) %c%c%"U16_F" 0x%08"X32_F"\n", | |
(void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num, autoip->llipaddr.addr)); | |
IP4_ADDR(&sn_mask, 255, 255, 0, 0); | |
IP4_ADDR(&gw_addr, 0, 0, 0, 0); | |
netif_set_ipaddr(netif, &autoip->llipaddr); | |
netif_set_netmask(netif, &sn_mask); | |
netif_set_gw(netif, &gw_addr); | |
/* bring the interface up */ | |
netif_set_up(netif); | |
return ERR_OK; | |
} | |
/** | |
* Start AutoIP client | |
* | |
* @param netif network interface on which start the AutoIP client | |
*/ | |
err_t | |
autoip_start(struct netif *netif) | |
{ | |
struct autoip *autoip = netif->autoip; | |
err_t result = ERR_OK; | |
if(netif_is_up(netif)) { | |
netif_set_down(netif); | |
} | |
/* Set IP-Address, Netmask and Gateway to 0 to make sure that | |
* ARP Packets are formed correctly | |
*/ | |
netif->ip_addr.addr = 0; | |
netif->netmask.addr = 0; | |
netif->gw.addr = 0; | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, | |
("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], | |
netif->name[1], (u16_t)netif->num)); | |
if(autoip == NULL) { | |
/* no AutoIP client attached yet? */ | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, | |
("autoip_start(): starting new AUTOIP client\n")); | |
autoip = mem_malloc(sizeof(struct autoip)); | |
if(autoip == NULL) { | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, | |
("autoip_start(): could not allocate autoip\n")); | |
return ERR_MEM; | |
} | |
memset( autoip, 0, sizeof(struct autoip)); | |
/* store this AutoIP client in the netif */ | |
netif->autoip = autoip; | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip")); | |
} else { | |
autoip->state = AUTOIP_STATE_OFF; | |
autoip->ttw = 0; | |
autoip->sent_num = 0; | |
memset(&autoip->llipaddr, 0, sizeof(struct ip_addr)); | |
autoip->lastconflict = 0; | |
} | |
autoip_create_rand_addr(netif, &(autoip->llipaddr)); | |
autoip->tried_llipaddr++; | |
autoip->state = AUTOIP_STATE_PROBING; | |
autoip->sent_num = 0; | |
/* time to wait to first probe, this is randomly | |
* choosen out of 0 to PROBE_WAIT seconds. | |
* compliant to RFC 3927 Section 2.2.1 | |
*/ | |
autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND)); | |
/* | |
* if we tried more then MAX_CONFLICTS we must limit our rate for | |
* accquiring and probing address | |
* compliant to RFC 3927 Section 2.2.1 | |
*/ | |
if(autoip->tried_llipaddr > MAX_CONFLICTS) { | |
autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND; | |
} | |
return result; | |
} | |
/** | |
* Stop AutoIP client | |
* | |
* @param netif network interface on which stop the AutoIP client | |
*/ | |
err_t | |
autoip_stop(struct netif *netif) | |
{ | |
netif->autoip->state = AUTOIP_STATE_OFF; | |
netif_set_down(netif); | |
return ERR_OK; | |
} | |
/** | |
* Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds | |
*/ | |
void | |
autoip_tmr() | |
{ | |
struct netif *netif = netif_list; | |
/* loop through netif's */ | |
while (netif != NULL) { | |
/* only act on AutoIP configured interfaces */ | |
if (netif->autoip != NULL) { | |
if(netif->autoip->lastconflict > 0) { | |
netif->autoip->lastconflict--; | |
} | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, | |
("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n", | |
(u16_t)(netif->autoip->state), netif->autoip->ttw)); | |
switch(netif->autoip->state) { | |
case AUTOIP_STATE_PROBING: | |
if(netif->autoip->ttw > 0) { | |
netif->autoip->ttw--; | |
} else { | |
if(netif->autoip->sent_num == PROBE_NUM) { | |
netif->autoip->state = AUTOIP_STATE_ANNOUNCING; | |
netif->autoip->sent_num = 0; | |
netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND; | |
} else { | |
etharp_request(netif, &(netif->autoip->llipaddr)); | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, | |
("autoip_tmr() PROBING Sent Probe\n")); | |
netif->autoip->sent_num++; | |
/* calculate time to wait to next probe */ | |
netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) % | |
((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) + | |
PROBE_MIN * AUTOIP_TICKS_PER_SECOND); | |
} | |
} | |
break; | |
case AUTOIP_STATE_ANNOUNCING: | |
if(netif->autoip->ttw > 0) { | |
netif->autoip->ttw--; | |
} else { | |
if(netif->autoip->sent_num == 0) { | |
/* We are here the first time, so we waited ANNOUNCE_WAIT seconds | |
* Now we can bind to an IP address and use it | |
*/ | |
autoip_bind(netif); | |
} | |
if(netif->autoip->sent_num == ANNOUNCE_NUM) { | |
netif->autoip->state = AUTOIP_STATE_BOUND; | |
netif->autoip->sent_num = 0; | |
netif->autoip->ttw = 0; | |
} else { | |
autoip_arp_announce(netif); | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, | |
("autoip_tmr() ANNOUNCING Sent Announce\n")); | |
netif->autoip->sent_num++; | |
netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND; | |
} | |
} | |
break; | |
} | |
} | |
/* proceed to next network interface */ | |
netif = netif->next; | |
} | |
} | |
/** | |
* Handles every incoming ARP Packet, called by etharp_arp_input. | |
* | |
* @param netif network interface to use for autoip processing | |
* @param hdr Incoming ARP packet | |
*/ | |
void | |
autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr) | |
{ | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_arp_reply()\n")); | |
if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) { | |
/* when ip.src == llipaddr && hw.src != netif->hwaddr | |
* | |
* when probing ip.dst == llipaddr && hw.src != netif->hwaddr | |
* we have a conflict and must solve it | |
*/ | |
struct ip_addr sipaddr, dipaddr; | |
struct eth_addr netifaddr; | |
netifaddr.addr[0] = netif->hwaddr[0]; | |
netifaddr.addr[1] = netif->hwaddr[1]; | |
netifaddr.addr[2] = netif->hwaddr[2]; | |
netifaddr.addr[3] = netif->hwaddr[3]; | |
netifaddr.addr[4] = netif->hwaddr[4]; | |
netifaddr.addr[5] = netif->hwaddr[5]; | |
/* Copy struct ip_addr2 to aligned ip_addr, to support compilers without | |
* structure packing (not using structure copy which breaks strict-aliasing rules). | |
*/ | |
MEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr)); | |
MEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr)); | |
if ((netif->autoip->state == AUTOIP_STATE_PROBING) || | |
((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) && | |
(netif->autoip->sent_num == 0))) { | |
/* RFC 3927 Section 2.2.1: | |
* from beginning to after ANNOUNCE_WAIT | |
* seconds we have a conflict if | |
* ip.src == llipaddr OR | |
* ip.dst == llipaddr && hw.src != own hwaddr | |
*/ | |
if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) || | |
(ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) && | |
!eth_addr_cmp(&netifaddr, &hdr->shwaddr))) { | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_arp_reply(): Probe Conflict detected\n")); | |
autoip_start(netif); | |
} | |
} else { | |
/* RFC 3927 Section 2.5: | |
* in any state we have a conflict if | |
* ip.src == llipaddr && hw.src != own hwaddr | |
*/ | |
if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) && | |
!eth_addr_cmp(&netifaddr, &hdr->shwaddr)) { | |
LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, | |
("autoip_arp_reply(): Conflicting ARP-Packet detected\n")); | |
autoip_handle_arp_conflict(netif); | |
} | |
} | |
} | |
} | |
#endif /* LWIP_AUTOIP */ |