1 /*
2 * dhcpcd - DHCP client daemon
3 * Copyright (c) 2006-2011 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 *
make_ipv4ll_lease(uint32_t addr)44 make_ipv4ll_lease(uint32_t 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 dhcp->yiaddr = addr;
53 p = dhcp->options;
54 *p++ = DHO_SUBNETMASK;
55 *p++ = sizeof(u32);
56 u32 = htonl(LINKLOCAL_MASK);
57 memcpy(p, &u32, sizeof(u32));
58 p += sizeof(u32);
59 *p++ = DHO_BROADCAST;
60 *p++ = sizeof(u32);
61 u32 = htonl(LINKLOCAL_BRDC);
62 memcpy(p, &u32, sizeof(u32));
63 p += sizeof(u32);
64 *p++ = DHO_END;
65
66 return dhcp;
67 }
68
69 static struct dhcp_message *
find_ipv4ll_lease(uint32_t old_addr)70 find_ipv4ll_lease(uint32_t old_addr)
71 {
72 uint32_t addr;
73
74 for (;;) {
75 addr = htonl(LINKLOCAL_ADDR |
76 (((uint32_t)abs((int)arc4random())
77 % 0xFD00) + 0x0100));
78 if (addr != old_addr &&
79 IN_LINKLOCAL(ntohl(addr)))
80 break;
81 }
82 return make_ipv4ll_lease(addr);
83 }
84
85 void
start_ipv4ll(void * arg)86 start_ipv4ll(void *arg)
87 {
88 struct interface *iface = arg;
89 uint32_t addr;
90
91 delete_timeout(NULL, iface);
92 iface->state->probes = 0;
93 iface->state->claims = 0;
94 if (iface->addr.s_addr) {
95 iface->state->conflicts = 0;
96 if (IN_LINKLOCAL(htonl(iface->addr.s_addr))) {
97 send_arp_announce(iface);
98 return;
99 }
100 }
101
102 if (iface->state->offer == NULL)
103 addr = 0;
104 else {
105 addr = iface->state->offer->yiaddr;
106 free(iface->state->offer);
107 }
108 /* We maybe rebooting an IPv4LL address. */
109 if (!IN_LINKLOCAL(htonl(addr))) {
110 syslog(LOG_INFO, "%s: probing for an IPv4LL address",
111 iface->name);
112 addr = 0;
113 }
114 if (addr == 0)
115 iface->state->offer = find_ipv4ll_lease(addr);
116 else
117 iface->state->offer = make_ipv4ll_lease(addr);
118 iface->state->lease.frominfo = 0;
119 send_arp_probe(iface);
120 }
121
122 void
handle_ipv4ll_failure(void * arg)123 handle_ipv4ll_failure(void *arg)
124 {
125 struct interface *iface = arg;
126 time_t up;
127
128 if (iface->state->fail.s_addr == iface->addr.s_addr) {
129 up = uptime();
130 if (iface->state->defend + DEFEND_INTERVAL > up) {
131 syslog(LOG_DEBUG,
132 "%s: IPv4LL %d second defence failed",
133 iface->name, DEFEND_INTERVAL);
134 drop_dhcp(iface, "EXPIRE");
135 iface->state->conflicts = -1;
136 } else {
137 syslog(LOG_DEBUG, "%s: defended IPv4LL address",
138 iface->name);
139 iface->state->defend = up;
140 return;
141 }
142 }
143
144 close_sockets(iface);
145 free(iface->state->offer);
146 iface->state->offer = NULL;
147 delete_timeout(NULL, iface);
148 if (++iface->state->conflicts > MAX_CONFLICTS) {
149 syslog(LOG_ERR, "%s: failed to acquire an IPv4LL address",
150 iface->name);
151 iface->state->interval = RATE_LIMIT_INTERVAL / 2;
152 start_discover(iface);
153 } else {
154 add_timeout_sec(PROBE_WAIT, start_ipv4ll, iface);
155 }
156 }
157