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lwip/src/core/ipv4/autoip.c

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/**
* @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>
*/
#include <stdlib.h>
#include <string.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"
#if LWIP_AUTOIP /* don't build if not configured for use in lwipopt.h */
/* static functions */
static void autoip_handle_arp_conflict(struct netif *netif);
/* creates random LL IP-Address */
static void autoip_create_rand_addr(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
* seed random with MAC-Address for creating pseudo-ramdom linc-local address
*/
void
autoip_init(void)
{
/* TODO MAC_ADDRESS macaddr; */
LWIP_DEBUGF(AUTOIP_DEBUG | DBG_TRACE | 3, ("autoip_init()\n"));
/* TODO Get_Current_MAC_Address(&macaddr);*/
/*srand(
(macaddr.addr[2] << 24) |
(macaddr.addr[3] << 16) |
(macaddr.addr[4] << 8) |
(macaddr.addr[5] << 0)
);*/
}
/**
* TODO: Add comment
*/
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 | DBG_TRACE | 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 | DBG_TRACE | DBG_STATE | 1, ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
autoip_arp_announce(netif);
netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_FINE_TIMER_TICK_PER_SECOND;
}
} else {
LWIP_DEBUGF(AUTOIP_DEBUG | DBG_TRACE | DBG_STATE | 1, ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
/* TODO: close all TCP sessions */
autoip_start(netif);
}
}
/**
* TODO: Add comment
*/
static void
autoip_create_rand_addr(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 = htonl((u32_t)(rand() % (0xA9FEFEFF + 1 - 0xA9FE0100) + 0xA9FE0100));
}
/**
* TODO: Add comment
*/
static err_t
autoip_arp_announce(struct netif *netif)
{
struct eth_addr eth_addr_bc, eth_addr_zero;
u8_t k = netif->hwaddr_len;
while(k > 0) {
k--;
eth_addr_bc.addr[k] = 0xFF;
eth_addr_zero.addr[k] = 0x00;
}
return etharp_raw( netif,
(struct eth_addr *)netif->hwaddr,
&eth_addr_bc,
(struct eth_addr *)netif->hwaddr,
&netif->autoip->llipaddr,
&eth_addr_zero,
&netif->autoip->llipaddr,
ARP_REQUEST
);
}
/**
* TODO: Add comment
*/
static err_t
autoip_bind(struct netif *netif)
{
struct autoip *autoip = netif->autoip;
struct ip_addr sn_mask, gw_addr;
LWIP_DEBUGF(AUTOIP_DEBUG | DBG_TRACE | 3, ("autoip_bind(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
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;
}
/**
* TODO: Add comment
*/
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 | DBG_TRACE | 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 | DBG_TRACE, ("autoip_start(): starting new AUTOIP client\n"));
autoip = mem_malloc(sizeof(struct autoip));
if(autoip == NULL) {
LWIP_DEBUGF(AUTOIP_DEBUG | 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 | 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(&(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 = (rand() % (PROBE_WAIT * AUTOIP_FINE_TIMER_TICK_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_FINE_TIMER_TICK_PER_SECOND;
}
return result;
}
/**
* TODO: Add comment
*/
err_t
autoip_stop(struct netif *netif)
{
netif->autoip->state = AUTOIP_STATE_OFF;
netif_set_down(netif);
return ERR_OK;
}
/**
* TODO: Add comment
*/
void
autoip_fine_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 | DBG_TRACE | 3, ("autoip_fine_tmr()AutoIP-Sate: %d\n", netif->autoip->state));
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_FINE_TIMER_TICK_PER_SECOND;
} else {
etharp_request(netif, &(netif->autoip->llipaddr));
LWIP_DEBUGF(AUTOIP_DEBUG | DBG_TRACE | 3, ("autoip_fine_tmr() PROBING Sent Probe\n"));
netif->autoip->sent_num++;
/* calculate time to wait to next probe */
netif->autoip->ttw = (rand() % ((PROBE_MAX - PROBE_MIN) * AUTOIP_FINE_TIMER_TICK_PER_SECOND) ) + PROBE_MIN * AUTOIP_FINE_TIMER_TICK_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 | DBG_TRACE | 3, ("autoip_fine_tmr() ANNOUNCING Sent Announce\n"));
netif->autoip->sent_num++;
netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_FINE_TIMER_TICK_PER_SECOND;
}
}
break;
}
}
/* proceed to next network interface */
netif = netif->next;
}
}
/**
* TODO: Add comment
*/
void
autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
{
LWIP_DEBUGF(AUTOIP_DEBUG | 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 | DBG_TRACE | 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 | DBG_TRACE | DBG_STATE | 1, ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
autoip_handle_arp_conflict(netif);
}
}
}
}
#endif /* LWIP_AUTOIP */
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