www.pudn.com > lwip-1.3.0.rar > autoip.c
/**
* @file
* AutoIP Automatic LinkLocal IP Configuration
*
*/
/*
*
* Copyright (c) 2007 Dominik Spies
* 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
*
* 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
*
*/
/*******************************************************************************
* 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
#include
/* 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 */