1 | /* |
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2 | * dhcpcd - DHCP client daemon |
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3 | * Copyright (c) 2006-2014 Roy Marples <roy@marples.name> |
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4 | * All rights reserved |
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5 | |
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6 | * Redistribution and use in source and binary forms, with or without |
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7 | * modification, are permitted provided that the following conditions |
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8 | * are met: |
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9 | * 1. Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * 2. Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * |
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15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
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16 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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17 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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18 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
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19 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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20 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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21 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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22 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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23 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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24 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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25 | * SUCH DAMAGE. |
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26 | */ |
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27 | |
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28 | #include <errno.h> |
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29 | #include <signal.h> |
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30 | #include <stdlib.h> |
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31 | #include <string.h> |
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32 | #include <syslog.h> |
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33 | #include <unistd.h> |
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34 | |
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35 | #include "config.h" |
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36 | #include "arp.h" |
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37 | #include "common.h" |
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38 | #include "dhcp.h" |
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39 | #include "eloop.h" |
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40 | #include "if-options.h" |
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41 | #include "ipv4ll.h" |
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42 | #include "net.h" |
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43 | |
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44 | static struct dhcp_message * |
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45 | ipv4ll_make_lease(uint32_t addr) |
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46 | { |
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47 | uint32_t u32; |
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48 | struct dhcp_message *dhcp; |
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49 | uint8_t *p; |
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50 | |
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51 | dhcp = calloc(1, sizeof(*dhcp)); |
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52 | if (dhcp == NULL) |
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53 | return NULL; |
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54 | /* Put some LL options in */ |
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55 | dhcp->yiaddr = addr; |
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56 | p = dhcp->options; |
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57 | *p++ = DHO_SUBNETMASK; |
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58 | *p++ = sizeof(u32); |
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59 | u32 = htonl(LINKLOCAL_MASK); |
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60 | memcpy(p, &u32, sizeof(u32)); |
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61 | p += sizeof(u32); |
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62 | *p++ = DHO_BROADCAST; |
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63 | *p++ = sizeof(u32); |
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64 | u32 = htonl(LINKLOCAL_BRDC); |
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65 | memcpy(p, &u32, sizeof(u32)); |
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66 | p += sizeof(u32); |
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67 | *p++ = DHO_END; |
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68 | |
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69 | return dhcp; |
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70 | } |
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71 | |
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72 | static struct dhcp_message * |
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73 | ipv4ll_find_lease(uint32_t old_addr) |
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74 | { |
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75 | uint32_t addr; |
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76 | |
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77 | for (;;) { |
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78 | addr = htonl(LINKLOCAL_ADDR | |
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79 | (((uint32_t)abs((int)arc4random()) |
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80 | % 0xFD00) + 0x0100)); |
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81 | if (addr != old_addr && |
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82 | IN_LINKLOCAL(ntohl(addr))) |
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83 | break; |
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84 | } |
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85 | return ipv4ll_make_lease(addr); |
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86 | } |
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87 | |
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88 | void |
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89 | ipv4ll_start(void *arg) |
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90 | { |
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91 | struct interface *ifp = arg; |
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92 | struct dhcp_state *state = D_STATE(ifp); |
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93 | uint32_t addr; |
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94 | |
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95 | eloop_timeout_delete(NULL, ifp); |
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96 | state->probes = 0; |
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97 | state->claims = 0; |
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98 | if (state->addr.s_addr) { |
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99 | state->conflicts = 0; |
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100 | if (IN_LINKLOCAL(htonl(state->addr.s_addr))) { |
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101 | arp_announce(ifp); |
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102 | return; |
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103 | } |
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104 | } |
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105 | |
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106 | if (state->offer == NULL) |
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107 | addr = 0; |
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108 | else { |
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109 | addr = state->offer->yiaddr; |
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110 | free(state->offer); |
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111 | } |
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112 | /* We maybe rebooting an IPv4LL address. */ |
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113 | if (!IN_LINKLOCAL(htonl(addr))) { |
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114 | syslog(LOG_INFO, "%s: probing for an IPv4LL address", |
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115 | ifp->name); |
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116 | addr = 0; |
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117 | } |
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118 | if (addr == 0) |
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119 | state->offer = ipv4ll_find_lease(addr); |
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120 | else |
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121 | state->offer = ipv4ll_make_lease(addr); |
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122 | if (state->offer == NULL) |
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123 | syslog(LOG_ERR, "%s: %m", __func__); |
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124 | else { |
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125 | state->lease.frominfo = 0; |
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126 | arp_probe(ifp); |
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127 | } |
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128 | } |
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129 | |
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130 | void |
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131 | ipv4ll_handle_failure(void *arg) |
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132 | { |
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133 | struct interface *ifp = arg; |
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134 | struct dhcp_state *state = D_STATE(ifp); |
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135 | time_t up; |
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136 | |
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137 | if (state->fail.s_addr == state->addr.s_addr) { |
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138 | /* RFC 3927 Section 2.5 */ |
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139 | up = uptime(); |
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140 | if (state->defend + DEFEND_INTERVAL > up) { |
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141 | syslog(LOG_WARNING, |
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142 | "%s: IPv4LL %d second defence failed", |
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143 | ifp->name, DEFEND_INTERVAL); |
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144 | dhcp_drop(ifp, "EXPIRE"); |
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145 | state->conflicts = -1; |
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146 | } else { |
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147 | syslog(LOG_DEBUG, "%s: defended IPv4LL address", |
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148 | ifp->name); |
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149 | state->defend = up; |
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150 | return; |
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151 | } |
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152 | } |
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153 | |
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154 | dhcp_close(ifp); |
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155 | free(state->offer); |
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156 | state->offer = NULL; |
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157 | eloop_timeout_delete(NULL, ifp); |
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158 | if (++state->conflicts > MAX_CONFLICTS) { |
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159 | syslog(LOG_ERR, "%s: failed to acquire an IPv4LL address", |
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160 | ifp->name); |
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161 | if (ifp->options->options & DHCPCD_DHCP) { |
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162 | state->interval = RATE_LIMIT_INTERVAL / 2; |
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163 | dhcp_discover(ifp); |
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164 | } else |
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165 | eloop_timeout_add_sec(RATE_LIMIT_INTERVAL, |
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166 | ipv4ll_start, ifp); |
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167 | } else { |
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168 | eloop_timeout_add_sec(PROBE_WAIT, ipv4ll_start, ifp); |
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169 | } |
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170 | } |
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