1 /* 2 * dhcpcd - DHCP client daemon 3 * Copyright (c) 2006-2011 Roy Marples <roy (at) 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 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 * 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 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 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
