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1 | office | 1 | /** |
2 | * @file BArpProbe.c |
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3 | * @author Ambroz Bizjak <ambrop7@gmail.com> |
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4 | * |
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5 | * @section LICENSE |
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6 | * |
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7 | * Redistribution and use in source and binary forms, with or without |
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8 | * modification, are permitted provided that the following conditions 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 | * 3. Neither the name of the author nor the |
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15 | * names of its contributors may be used to endorse or promote products |
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16 | * derived from this software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND |
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19 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
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20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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21 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
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22 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
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23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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24 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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25 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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27 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | */ |
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29 | |||
30 | #include <stdio.h> |
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31 | #include <string.h> |
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32 | #include <unistd.h> |
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33 | #include <sys/socket.h> |
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34 | #include <net/if.h> |
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35 | #include <net/if_arp.h> |
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36 | #include <sys/ioctl.h> |
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37 | #include <linux/filter.h> |
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38 | |||
39 | #include <misc/debug.h> |
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40 | #include <misc/byteorder.h> |
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41 | #include <misc/ethernet_proto.h> |
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42 | #include <misc/ipv4_proto.h> |
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43 | #include <misc/udp_proto.h> |
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44 | #include <misc/get_iface_info.h> |
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45 | #include <base/BLog.h> |
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46 | |||
47 | #include "BArpProbe.h" |
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48 | |||
49 | #include <generated/blog_channel_BArpProbe.h> |
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50 | |||
51 | #define STATE_INITIAL 1 |
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52 | #define STATE_NOEXIST 2 |
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53 | #define STATE_EXIST 3 |
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54 | #define STATE_EXIST_PANIC 4 |
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55 | |||
56 | static void dgram_handler (BArpProbe *o, int event) |
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57 | { |
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58 | DebugObject_Access(&o->d_obj); |
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59 | |||
60 | BLog(BLOG_ERROR, "packet socket error"); |
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61 | |||
62 | // report error |
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63 | DEBUGERROR(&o->d_err, o->handler(o->user, BARPPROBE_EVENT_ERROR)); |
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64 | return; |
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65 | } |
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66 | |||
67 | static void send_request (BArpProbe *o) |
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68 | { |
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69 | if (o->send_sending) { |
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70 | BLog(BLOG_ERROR, "cannot send packet while another packet is being sent!"); |
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71 | return; |
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72 | } |
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73 | |||
74 | // build packet |
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75 | struct arp_packet *arp = &o->send_packet; |
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76 | arp->hardware_type = hton16(ARP_HARDWARE_TYPE_ETHERNET); |
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77 | arp->protocol_type = hton16(ETHERTYPE_IPV4); |
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78 | arp->hardware_size = hton8(6); |
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79 | arp->protocol_size = hton8(4); |
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80 | arp->opcode = hton16(ARP_OPCODE_REQUEST); |
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81 | memcpy(arp->sender_mac, o->if_mac, 6); |
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82 | arp->sender_ip = hton32(0); |
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83 | memset(arp->target_mac, 0, sizeof(arp->target_mac)); |
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84 | arp->target_ip = o->addr; |
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85 | |||
86 | // send packet |
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87 | PacketPassInterface_Sender_Send(o->send_if, (uint8_t *)&o->send_packet, sizeof(o->send_packet)); |
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88 | |||
89 | // set sending |
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90 | o->send_sending = 1; |
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91 | } |
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92 | |||
93 | static void send_if_handler_done (BArpProbe *o) |
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94 | { |
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95 | DebugObject_Access(&o->d_obj); |
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96 | ASSERT(o->send_sending) |
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97 | |||
98 | // set not sending |
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99 | o->send_sending = 0; |
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100 | } |
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101 | |||
102 | static void recv_if_handler_done (BArpProbe *o, int data_len) |
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103 | { |
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104 | DebugObject_Access(&o->d_obj); |
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105 | ASSERT(data_len >= 0) |
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106 | ASSERT(data_len <= sizeof(struct arp_packet)) |
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107 | |||
108 | // receive next packet |
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109 | PacketRecvInterface_Receiver_Recv(o->recv_if, (uint8_t *)&o->recv_packet); |
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110 | |||
111 | if (data_len != sizeof(struct arp_packet)) { |
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112 | BLog(BLOG_WARNING, "receive: wrong size"); |
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113 | return; |
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114 | } |
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115 | |||
116 | struct arp_packet *arp = &o->recv_packet; |
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117 | |||
118 | if (ntoh16(arp->hardware_type) != ARP_HARDWARE_TYPE_ETHERNET) { |
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119 | BLog(BLOG_WARNING, "receive: wrong hardware type"); |
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120 | return; |
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121 | } |
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122 | |||
123 | if (ntoh16(arp->protocol_type) != ETHERTYPE_IPV4) { |
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124 | BLog(BLOG_WARNING, "receive: wrong protocol type"); |
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125 | return; |
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126 | } |
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127 | |||
128 | if (ntoh8(arp->hardware_size) != 6) { |
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129 | BLog(BLOG_WARNING, "receive: wrong hardware size"); |
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130 | return; |
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131 | } |
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132 | |||
133 | if (ntoh8(arp->protocol_size) != 4) { |
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134 | BLog(BLOG_WARNING, "receive: wrong protocol size"); |
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135 | return; |
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136 | } |
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137 | |||
138 | if (ntoh16(arp->opcode) != ARP_OPCODE_REPLY) { |
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139 | return; |
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140 | } |
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141 | |||
142 | if (arp->sender_ip != o->addr) { |
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143 | return; |
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144 | } |
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145 | |||
146 | int old_state = o->state; |
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147 | |||
148 | // set minus one missed |
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149 | o->num_missed = -1; |
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150 | |||
151 | // set timer |
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152 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_WAITSEND); |
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153 | |||
154 | // set state exist |
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155 | o->state = STATE_EXIST; |
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156 | |||
157 | // report exist if needed |
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158 | if (old_state == STATE_INITIAL || old_state == STATE_NOEXIST) { |
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159 | o->handler(o->user, BARPPROBE_EVENT_EXIST); |
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160 | return; |
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161 | } |
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162 | } |
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163 | |||
164 | static void timer_handler (BArpProbe *o) |
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165 | { |
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166 | DebugObject_Access(&o->d_obj); |
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167 | |||
168 | // send request |
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169 | send_request(o); |
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170 | |||
171 | switch (o->state) { |
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172 | case STATE_INITIAL: { |
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173 | ASSERT(o->num_missed >= 0) |
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174 | ASSERT(o->num_missed < BARPPROBE_INITIAL_NUM_ATTEMPTS) |
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175 | |||
176 | // increment missed |
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177 | o->num_missed++; |
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178 | |||
179 | // all attempts failed? |
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180 | if (o->num_missed == BARPPROBE_INITIAL_NUM_ATTEMPTS) { |
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181 | // set timer |
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182 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV); |
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183 | |||
184 | // set state noexist |
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185 | o->state = STATE_NOEXIST; |
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186 | |||
187 | // report noexist |
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188 | o->handler(o->user, BARPPROBE_EVENT_NOEXIST); |
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189 | return; |
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190 | } |
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191 | |||
192 | // set timer |
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193 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_INITIAL_WAITRECV); |
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194 | } break; |
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195 | |||
196 | case STATE_NOEXIST: { |
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197 | // set timer |
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198 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV); |
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199 | } break; |
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200 | |||
201 | case STATE_EXIST: { |
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202 | ASSERT(o->num_missed >= -1) |
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203 | ASSERT(o->num_missed < BARPPROBE_EXIST_NUM_NOREPLY) |
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204 | |||
205 | // increment missed |
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206 | o->num_missed++; |
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207 | |||
208 | // all missed? |
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209 | if (o->num_missed == BARPPROBE_EXIST_NUM_NOREPLY) { |
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210 | // set timer |
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211 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_PANIC_WAITRECV); |
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212 | |||
213 | // set zero missed |
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214 | o->num_missed = 0; |
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215 | |||
216 | // set state panic |
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217 | o->state = STATE_EXIST_PANIC; |
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218 | return; |
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219 | } |
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220 | |||
221 | // set timer |
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222 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_WAITRECV); |
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223 | } break; |
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224 | |||
225 | case STATE_EXIST_PANIC: { |
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226 | ASSERT(o->num_missed >= 0) |
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227 | ASSERT(o->num_missed < BARPPROBE_EXIST_PANIC_NUM_NOREPLY) |
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228 | |||
229 | // increment missed |
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230 | o->num_missed++; |
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231 | |||
232 | // all missed? |
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233 | if (o->num_missed == BARPPROBE_EXIST_PANIC_NUM_NOREPLY) { |
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234 | // set timer |
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235 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_NOEXIST_WAITRECV); |
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236 | |||
237 | // set state panic |
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238 | o->state = STATE_NOEXIST; |
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239 | |||
240 | // report noexist |
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241 | o->handler(o->user, BARPPROBE_EVENT_NOEXIST); |
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242 | return; |
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243 | } |
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244 | |||
245 | // set timer |
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246 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_EXIST_PANIC_WAITRECV); |
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247 | } break; |
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248 | } |
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249 | } |
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250 | |||
251 | int BArpProbe_Init (BArpProbe *o, const char *ifname, uint32_t addr, BReactor *reactor, void *user, BArpProbe_handler handler) |
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252 | { |
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253 | ASSERT(ifname) |
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254 | ASSERT(handler) |
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255 | |||
256 | // init arguments |
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257 | o->addr = addr; |
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258 | o->reactor = reactor; |
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259 | o->user = user; |
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260 | o->handler = handler; |
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261 | |||
262 | // get interface information |
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263 | int if_mtu; |
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264 | int if_index; |
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265 | if (!badvpn_get_iface_info(ifname, o->if_mac, &if_mtu, &if_index)) { |
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266 | BLog(BLOG_ERROR, "failed to get interface information"); |
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267 | goto fail0; |
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268 | } |
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269 | |||
270 | uint8_t *if_mac = o->if_mac; |
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271 | BLog(BLOG_INFO, "if_mac=%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8" if_mtu=%d if_index=%d", |
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272 | if_mac[0], if_mac[1], if_mac[2], if_mac[3], if_mac[4], if_mac[5], if_mtu, if_index); |
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273 | |||
274 | // check MTU |
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275 | if (if_mtu < sizeof(struct arp_packet)) { |
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276 | BLog(BLOG_ERROR, "MTU is too small for ARP !?!"); |
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277 | goto fail0; |
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278 | } |
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279 | |||
280 | // init dgram |
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281 | if (!BDatagram_Init(&o->dgram, BADDR_TYPE_PACKET, o->reactor, o, (BDatagram_handler)dgram_handler)) { |
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282 | BLog(BLOG_ERROR, "BDatagram_Init failed"); |
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283 | goto fail0; |
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284 | } |
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285 | |||
286 | // bind dgram |
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287 | BAddr bind_addr; |
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288 | BAddr_InitPacket(&bind_addr, hton16(ETHERTYPE_ARP), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_HOST, if_mac); |
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289 | if (!BDatagram_Bind(&o->dgram, bind_addr)) { |
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290 | BLog(BLOG_ERROR, "BDatagram_Bind failed"); |
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291 | goto fail1; |
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292 | } |
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293 | |||
294 | // set dgram send addresses |
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295 | BAddr dest_addr; |
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296 | uint8_t broadcast_mac[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; |
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297 | BAddr_InitPacket(&dest_addr, hton16(ETHERTYPE_ARP), if_index, BADDR_PACKET_HEADER_TYPE_ETHERNET, BADDR_PACKET_PACKET_TYPE_BROADCAST, broadcast_mac); |
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298 | BIPAddr local_addr; |
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299 | BIPAddr_InitInvalid(&local_addr); |
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300 | BDatagram_SetSendAddrs(&o->dgram, dest_addr, local_addr); |
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301 | |||
302 | // init send interface |
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303 | BDatagram_SendAsync_Init(&o->dgram, sizeof(struct arp_packet)); |
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304 | o->send_if = BDatagram_SendAsync_GetIf(&o->dgram); |
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305 | PacketPassInterface_Sender_Init(o->send_if, (PacketPassInterface_handler_done)send_if_handler_done, o); |
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306 | |||
307 | // set not sending |
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308 | o->send_sending = 0; |
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309 | |||
310 | // init recv interface |
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311 | BDatagram_RecvAsync_Init(&o->dgram, sizeof(struct arp_packet)); |
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312 | o->recv_if = BDatagram_RecvAsync_GetIf(&o->dgram); |
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313 | PacketRecvInterface_Receiver_Init(o->recv_if, (PacketRecvInterface_handler_done)recv_if_handler_done, o); |
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314 | |||
315 | // init timer |
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316 | BTimer_Init(&o->timer, 0, (BTimer_handler)timer_handler, o); |
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317 | |||
318 | // receive first packet |
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319 | PacketRecvInterface_Receiver_Recv(o->recv_if, (uint8_t *)&o->recv_packet); |
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320 | |||
321 | // send request |
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322 | send_request(o); |
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323 | |||
324 | // set timer |
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325 | BReactor_SetTimerAfter(o->reactor, &o->timer, BARPPROBE_INITIAL_WAITRECV); |
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326 | |||
327 | // set zero missed |
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328 | o->num_missed = 0; |
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329 | |||
330 | // set state initial |
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331 | o->state = STATE_INITIAL; |
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332 | |||
333 | DebugError_Init(&o->d_err, BReactor_PendingGroup(o->reactor)); |
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334 | DebugObject_Init(&o->d_obj); |
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335 | return 1; |
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336 | |||
337 | fail1: |
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338 | BDatagram_Free(&o->dgram); |
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339 | fail0: |
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340 | return 0; |
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341 | } |
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342 | |||
343 | void BArpProbe_Free (BArpProbe *o) |
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344 | { |
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345 | DebugObject_Free(&o->d_obj); |
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346 | DebugError_Free(&o->d_err); |
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347 | |||
348 | // free timer |
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349 | BReactor_RemoveTimer(o->reactor, &o->timer); |
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350 | |||
351 | // free recv interface |
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352 | BDatagram_RecvAsync_Free(&o->dgram); |
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353 | |||
354 | // free send interface |
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355 | BDatagram_SendAsync_Free(&o->dgram); |
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356 | |||
357 | // free dgram |
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358 | BDatagram_Free(&o->dgram); |
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359 | } |