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/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2014 Roy Marples <roy@marples.name>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*/
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "config.h"
#include "arp.h"
#include "common.h"
#include "dhcp.h"
#include "eloop.h"
#include "if-options.h"
#include "ipv4ll.h"
#include "net.h"
static struct dhcp_message *
ipv4ll_make_lease(uint32_t addr)
{
uint32_t u32;
struct dhcp_message *dhcp;
uint8_t *p;
dhcp = calloc(1, sizeof(*dhcp));
if (dhcp == NULL)
return NULL;
/* Put some LL options in */
dhcp->yiaddr = addr;
p = dhcp->options;
*p++ = DHO_SUBNETMASK;
*p++ = sizeof(u32);
u32 = htonl(LINKLOCAL_MASK);
memcpy(p, &u32, sizeof(u32));
p += sizeof(u32);
*p++ = DHO_BROADCAST;
*p++ = sizeof(u32);
u32 = htonl(LINKLOCAL_BRDC);
memcpy(p, &u32, sizeof(u32));
p += sizeof(u32);
*p++ = DHO_END;
return dhcp;
}
static struct dhcp_message *
ipv4ll_find_lease(uint32_t old_addr)
{
uint32_t addr;
for (;;) {
addr = htonl(LINKLOCAL_ADDR |
(((uint32_t)abs((int)arc4random())
% 0xFD00) + 0x0100));
if (addr != old_addr &&
IN_LINKLOCAL(ntohl(addr)))
break;
}
return ipv4ll_make_lease(addr);
}
void
ipv4ll_start(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
uint32_t addr;
eloop_timeout_delete(NULL, ifp);
state->probes = 0;
state->claims = 0;
if (state->addr.s_addr) {
state->conflicts = 0;
if (IN_LINKLOCAL(htonl(state->addr.s_addr))) {
arp_announce(ifp);
return;
}
}
if (state->offer == NULL)
addr = 0;
else {
addr = state->offer->yiaddr;
free(state->offer);
}
/* We maybe rebooting an IPv4LL address. */
if (!IN_LINKLOCAL(htonl(addr))) {
syslog(LOG_INFO, "%s: probing for an IPv4LL address",
ifp->name);
addr = 0;
}
if (addr == 0)
state->offer = ipv4ll_find_lease(addr);
else
state->offer = ipv4ll_make_lease(addr);
if (state->offer == NULL)
syslog(LOG_ERR, "%s: %m", __func__);
else {
state->lease.frominfo = 0;
arp_probe(ifp);
}
}
void
ipv4ll_handle_failure(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
time_t up;
if (state->fail.s_addr == state->addr.s_addr) {
/* RFC 3927 Section 2.5 */
up = uptime();
if (state->defend + DEFEND_INTERVAL > up) {
syslog(LOG_WARNING,
"%s: IPv4LL %d second defence failed",
ifp->name, DEFEND_INTERVAL);
dhcp_drop(ifp, "EXPIRE");
state->conflicts = -1;
} else {
syslog(LOG_DEBUG, "%s: defended IPv4LL address",
ifp->name);
state->defend = up;
return;
}
}
dhcp_close(ifp);
free(state->offer);
state->offer = NULL;
eloop_timeout_delete(NULL, ifp);
if (++state->conflicts > MAX_CONFLICTS) {
syslog(LOG_ERR, "%s: failed to acquire an IPv4LL address",
ifp->name);
if (ifp->options->options & DHCPCD_DHCP) {
state->interval = RATE_LIMIT_INTERVAL / 2;
dhcp_discover(ifp);
} else
eloop_timeout_add_sec(RATE_LIMIT_INTERVAL,
ipv4ll_start, ifp);
} else {
eloop_timeout_add_sec(PROBE_WAIT, ipv4ll_start, ifp);
}
}
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