external/bsd/dhcpcd/dist/ipv4ll.c

   1 /*
   2  * dhcpcd - DHCP client daemon
   3  * Copyright (c) 2006-2008 Roy Marples <roy@marples.name>
   4  * All rights reserved
   5
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <errno.h>
  29 #include <signal.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <syslog.h>
  33 #include <unistd.h>
  34
  35 #include "arp.h"
  36 #include "common.h"
  37 #include "dhcpcd.h"
  38 #include "eloop.h"
  39 #include "if-options.h"
  40 #include "ipv4ll.h"
  41 #include "net.h"
  42
  43 static struct dhcp_message*
  44 make_ipv4ll_lease(uint32_t old_addr)
  45 {
  46         uint32_t u32;
  47         struct dhcp_message *dhcp;
  48         uint8_t *p;
  49
  50         dhcp = xzalloc(sizeof(*dhcp));
  51         /* Put some LL options in */
  52         p = dhcp->options;
  53         *p++ = DHO_SUBNETMASK;
  54         *p++ = sizeof(u32);
  55         u32 = htonl(LINKLOCAL_MASK);
  56         memcpy(p, &u32, sizeof(u32));
  57         p += sizeof(u32);
  58         *p++ = DHO_BROADCAST;
  59         *p++ = sizeof(u32);
  60         u32 = htonl(LINKLOCAL_BRDC);
  61         memcpy(p, &u32, sizeof(u32));
  62         p += sizeof(u32);
  63         *p++ = DHO_END;
  64
  65         for (;;) {
  66                 dhcp->yiaddr = htonl(LINKLOCAL_ADDR |
  67                     (((uint32_t)abs((int)arc4random())
  68                         % 0xFD00) + 0x0100));
  69                 if (dhcp->yiaddr != old_addr &&
  70                     IN_LINKLOCAL(ntohl(dhcp->yiaddr)))
  71                         break;
  72         }
  73         return dhcp;
  74 }
  75
  76 void
  77 start_ipv4ll(void *arg)
  78 {
  79         struct interface *iface = arg;
  80
  81         iface->state->probes = 0;
  82         iface->state->claims = 0;
  83         if (iface->addr.s_addr) {
  84                 iface->state->conflicts = 0;
  85                 if (IN_LINKLOCAL(htonl(iface->addr.s_addr))) {
  86                         send_arp_announce(iface);
  87                         return;
  88                 }
  89         }
  90
  91         /* We maybe rebooting an IPv4LL address. */
  92         if (!iface->state->offer ||
  93             !IN_LINKLOCAL(htonl(iface->state->offer->yiaddr)))
  94         {
  95                 syslog(LOG_INFO, "%s: probing for an IPv4LL address",
  96                     iface->name);
  97                 delete_timeout(NULL, iface);
  98                 free(iface->state->offer);
  99                 iface->state->offer = make_ipv4ll_lease(0);
 100                 iface->state->lease.frominfo = 0;
 101         }
 102         send_arp_probe(iface);
 103 }
 104
 105 void
 106 handle_ipv4ll_failure(void *arg)
 107 {
 108         struct interface *iface = arg;
 109         time_t up;
 110
 111         if (iface->state->fail.s_addr == iface->state->lease.addr.s_addr) {
 112                 up = uptime();
 113                 if (iface->state->defend + DEFEND_INTERVAL > up) {
 114                         drop_config(iface, "EXPIRE");
 115                         iface->state->conflicts = -1;
 116                 } else {
 117                         iface->state->defend = up;
 118                         return;
 119                 }
 120         }
 121
 122         close_sockets(iface);
 123         free(iface->state->offer);
 124         iface->state->offer = NULL;
 125         if (++iface->state->conflicts > MAX_CONFLICTS) {
 126                 syslog(LOG_ERR, "%s: failed to acquire an IPv4LL address",
 127                     iface->name);
 128                 iface->state->interval = RATE_LIMIT_INTERVAL / 2;
 129                 start_discover(iface);
 130         } else {
 131                 add_timeout_sec(PROBE_WAIT, start_ipv4ll, iface);
 132         }
 133 }