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1 | office | 1 | /** |
2 | * @file DHCPIpUdpEncoder.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 <limits.h> |
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31 | #include <string.h> |
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32 | #include <stddef.h> |
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33 | |||
34 | #include <misc/ipv4_proto.h> |
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35 | #include <misc/udp_proto.h> |
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36 | #include <misc/byteorder.h> |
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37 | |||
38 | #include <dhcpclient/DHCPIpUdpEncoder.h> |
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39 | |||
40 | #define DHCP_SERVER_PORT 67 |
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41 | #define DHCP_CLIENT_PORT 68 |
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42 | |||
43 | #define IPUDP_HEADER_SIZE (sizeof(struct ipv4_header) + sizeof(struct udp_header)) |
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44 | |||
45 | static void output_handler_recv (DHCPIpUdpEncoder *o, uint8_t *data) |
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46 | { |
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47 | DebugObject_Access(&o->d_obj); |
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48 | |||
49 | // remember output packet |
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50 | o->data = data; |
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51 | |||
52 | // receive payload |
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53 | PacketRecvInterface_Receiver_Recv(o->input, o->data + IPUDP_HEADER_SIZE); |
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54 | } |
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55 | |||
56 | static void input_handler_done (DHCPIpUdpEncoder *o, int data_len) |
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57 | { |
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58 | DebugObject_Access(&o->d_obj); |
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59 | |||
60 | // build IP header |
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61 | struct ipv4_header iph; |
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62 | iph.version4_ihl4 = IPV4_MAKE_VERSION_IHL(sizeof(iph)); |
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63 | iph.ds = hton8(0); |
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64 | iph.total_length = hton16(IPUDP_HEADER_SIZE + data_len); |
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65 | iph.identification = hton16(0); |
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66 | iph.flags3_fragmentoffset13 = hton16(0); |
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67 | iph.ttl = hton8(64); |
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68 | iph.protocol = hton8(IPV4_PROTOCOL_UDP); |
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69 | iph.checksum = hton16(0); |
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70 | iph.source_address = hton32(0x00000000); |
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71 | iph.destination_address = hton32(0xFFFFFFFF); |
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72 | iph.checksum = ipv4_checksum(&iph, NULL, 0); |
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73 | |||
74 | // write UDP header |
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75 | struct udp_header udph; |
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76 | udph.source_port = hton16(DHCP_CLIENT_PORT); |
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77 | udph.dest_port = hton16(DHCP_SERVER_PORT); |
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78 | udph.length = hton16(sizeof(udph) + data_len); |
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79 | udph.checksum = hton16(0); |
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80 | udph.checksum = udp_checksum(&udph, o->data + IPUDP_HEADER_SIZE, data_len, iph.source_address, iph.destination_address); |
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81 | |||
82 | // write header |
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83 | memcpy(o->data, &iph, sizeof(iph)); |
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84 | memcpy(o->data + sizeof(iph), &udph, sizeof(udph)); |
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85 | |||
86 | // finish packet |
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87 | PacketRecvInterface_Done(&o->output, IPUDP_HEADER_SIZE + data_len); |
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88 | } |
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89 | |||
90 | void DHCPIpUdpEncoder_Init (DHCPIpUdpEncoder *o, PacketRecvInterface *input, BPendingGroup *pg) |
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91 | { |
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92 | ASSERT(PacketRecvInterface_GetMTU(input) <= INT_MAX - IPUDP_HEADER_SIZE) |
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93 | |||
94 | // init arguments |
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95 | o->input = input; |
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96 | |||
97 | // init input |
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98 | PacketRecvInterface_Receiver_Init(o->input, (PacketRecvInterface_handler_done)input_handler_done, o); |
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99 | |||
100 | // init output |
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101 | PacketRecvInterface_Init(&o->output, IPUDP_HEADER_SIZE + PacketRecvInterface_GetMTU(o->input), (PacketRecvInterface_handler_recv)output_handler_recv, o, pg); |
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102 | |||
103 | DebugObject_Init(&o->d_obj); |
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104 | } |
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105 | |||
106 | void DHCPIpUdpEncoder_Free (DHCPIpUdpEncoder *o) |
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107 | { |
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108 | DebugObject_Free(&o->d_obj); |
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109 | |||
110 | // free output |
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111 | PacketRecvInterface_Free(&o->output); |
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112 | } |
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113 | |||
114 | PacketRecvInterface * DHCPIpUdpEncoder_GetOutput (DHCPIpUdpEncoder *o) |
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115 | { |
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116 | DebugObject_Access(&o->d_obj); |
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117 | |||
118 | return &o->output; |
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119 | } |