1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * Russ Dill <Russ.Dill@asu.edu> September 2001
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4 | * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
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5 | *
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6 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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7 | */
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8 | #ifndef UDHCP_COMMON_H
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9 | #define UDHCP_COMMON_H 1
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10 |
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11 | #include "libbb.h"
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12 | #include <netinet/udp.h>
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13 | #include <netinet/ip.h>
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14 |
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15 | PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
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16 |
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17 | extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */
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18 |
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19 |
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20 | /*** DHCP packet ***/
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21 |
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22 | /* DHCP protocol. See RFC 2131 */
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23 | #define DHCP_MAGIC 0x63825363
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24 | #define DHCP_OPTIONS_BUFSIZE 308
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25 | #define BOOTREQUEST 1
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26 | #define BOOTREPLY 2
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27 |
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28 | //TODO: rename ciaddr/yiaddr/chaddr
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29 | struct dhcp_packet {
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30 | uint8_t op; /* BOOTREQUEST or BOOTREPLY */
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31 | uint8_t htype; /* hardware address type. 1 = 10mb ethernet */
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32 | uint8_t hlen; /* hardware address length */
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33 | uint8_t hops; /* used by relay agents only */
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34 | uint32_t xid; /* unique id */
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35 | uint16_t secs; /* elapsed since client began acquisition/renewal */
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36 | uint16_t flags; /* only one flag so far: */
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37 | #define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
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38 | uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
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39 | uint32_t yiaddr; /* 'your' (client) IP address */
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40 | /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
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41 | uint32_t siaddr_nip;
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42 | uint32_t gateway_nip; /* relay agent IP address */
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43 | uint8_t chaddr[16]; /* link-layer client hardware address (MAC) */
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44 | uint8_t sname[64]; /* server host name (ASCIZ) */
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45 | uint8_t file[128]; /* boot file name (ASCIZ) */
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46 | uint32_t cookie; /* fixed first four option bytes (99,130,83,99 dec) */
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47 | uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
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48 | } PACKED;
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49 | #define DHCP_PKT_SNAME_LEN 64
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50 | #define DHCP_PKT_FILE_LEN 128
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51 | #define DHCP_PKT_SNAME_LEN_STR "64"
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52 | #define DHCP_PKT_FILE_LEN_STR "128"
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53 |
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54 | struct ip_udp_dhcp_packet {
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55 | struct iphdr ip;
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56 | struct udphdr udp;
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57 | struct dhcp_packet data;
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58 | } PACKED;
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59 |
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60 | struct udp_dhcp_packet {
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61 | struct udphdr udp;
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62 | struct dhcp_packet data;
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63 | } PACKED;
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64 |
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65 | enum {
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66 | IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
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67 | UDP_DHCP_SIZE = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
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68 | DHCP_SIZE = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
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69 | };
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70 |
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71 | /* Let's see whether compiler understood us right */
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72 | struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
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73 | char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
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74 | };
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75 |
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76 |
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77 | /*** Options ***/
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78 |
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79 | enum {
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80 | OPTION_IP = 1,
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81 | OPTION_IP_PAIR,
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82 | OPTION_STRING,
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83 | // OPTION_BOOLEAN,
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84 | OPTION_U8,
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85 | OPTION_U16,
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86 | // OPTION_S16,
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87 | OPTION_U32,
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88 | OPTION_S32,
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89 | OPTION_BIN,
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90 | OPTION_STATIC_ROUTES,
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91 | #if ENABLE_FEATURE_UDHCP_RFC3397
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92 | OPTION_DNS_STRING, /* RFC1035 compressed domain name list */
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93 | OPTION_SIP_SERVERS,
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94 | #endif
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95 |
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96 | OPTION_TYPE_MASK = 0x0f,
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97 | /* Client requests this option by default */
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98 | OPTION_REQ = 0x10,
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99 | /* There can be a list of 1 or more of these */
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100 | OPTION_LIST = 0x20,
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101 | };
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102 |
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103 | /* DHCP option codes (partial list). See RFC 2132 and
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104 | * http://www.iana.org/assignments/bootp-dhcp-parameters/
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105 | * Commented out options are handled by common option machinery,
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106 | * uncommented ones have spacial cases (grep for them to see).
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107 | */
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108 | #define DHCP_PADDING 0x00
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109 | #define DHCP_SUBNET 0x01
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110 | //#define DHCP_TIME_OFFSET 0x02 /* (localtime - UTC_time) in seconds. signed */
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111 | //#define DHCP_ROUTER 0x03
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112 | //#define DHCP_TIME_SERVER 0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
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113 | //#define DHCP_NAME_SERVER 0x05 /* IEN 116 _really_ ancient kind of NS */
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114 | //#define DHCP_DNS_SERVER 0x06
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115 | //#define DHCP_LOG_SERVER 0x07 /* port 704 UDP log (not syslog)
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116 | //#define DHCP_COOKIE_SERVER 0x08 /* "quote of the day" server */
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117 | //#define DHCP_LPR_SERVER 0x09
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118 | #define DHCP_HOST_NAME 0x0c /* either client informs server or server gives name to client */
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119 | //#define DHCP_BOOT_SIZE 0x0d
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120 | //#define DHCP_DOMAIN_NAME 0x0f /* server gives domain suffix */
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121 | //#define DHCP_SWAP_SERVER 0x10
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122 | //#define DHCP_ROOT_PATH 0x11
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123 | //#define DHCP_IP_TTL 0x17
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124 | //#define DHCP_MTU 0x1a
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125 | //#define DHCP_BROADCAST 0x1c
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126 | //#define DHCP_ROUTES 0x21
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127 | //#define DHCP_NIS_DOMAIN 0x28
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128 | //#define DHCP_NIS_SERVER 0x29
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129 | //#define DHCP_NTP_SERVER 0x2a
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130 | //#define DHCP_WINS_SERVER 0x2c
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131 | #define DHCP_REQUESTED_IP 0x32 /* sent by client if specific IP is wanted */
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132 | #define DHCP_LEASE_TIME 0x33
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133 | #define DHCP_OPTION_OVERLOAD 0x34
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134 | #define DHCP_MESSAGE_TYPE 0x35
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135 | #define DHCP_SERVER_ID 0x36 /* by default server's IP */
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136 | #define DHCP_PARAM_REQ 0x37 /* list of options client wants */
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137 | //#define DHCP_ERR_MESSAGE 0x38 /* error message when sending NAK etc */
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138 | #define DHCP_MAX_SIZE 0x39
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139 | #define DHCP_VENDOR 0x3c /* client's vendor (a string) */
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140 | #define DHCP_CLIENT_ID 0x3d /* by default client's MAC addr, but may be arbitrarily long */
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141 | //#define DHCP_TFTP_SERVER_NAME 0x42 /* same as 'sname' field */
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142 | //#define DHCP_BOOT_FILE 0x43 /* same as 'file' field */
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143 | //#define DHCP_USER_CLASS 0x4d /* RFC 3004. set of LASCII strings. "I am a printer" etc */
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144 | #define DHCP_FQDN 0x51 /* client asks to update DNS to map its FQDN to its new IP */
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145 | //#define DHCP_DOMAIN_SEARCH 0x77 /* RFC 3397. set of ASCIZ string, DNS-style compressed */
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146 | //#define DHCP_SIP_SERVERS 0x78 /* RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
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147 | //#define DHCP_STATIC_ROUTES 0x79 /* RFC 3442. (mask,ip,router) tuples */
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148 | //#define DHCP_MS_STATIC_ROUTES 0xf9 /* Microsoft's pre-RFC 3442 code for 0x79? */
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149 | //#define DHCP_WPAD 0xfc /* MSIE's Web Proxy Autodiscovery Protocol */
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150 | #define DHCP_END 0xff
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151 |
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152 | /* Offsets in option byte sequence */
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153 | #define OPT_CODE 0
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154 | #define OPT_LEN 1
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155 | #define OPT_DATA 2
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156 | /* Bits in "overload" option */
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157 | #define OPTION_FIELD 0
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158 | #define FILE_FIELD 1
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159 | #define SNAME_FIELD 2
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160 |
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161 | /* DHCP_MESSAGE_TYPE values */
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162 | #define DHCPDISCOVER 1 /* client -> server */
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163 | #define DHCPOFFER 2 /* client <- server */
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164 | #define DHCPREQUEST 3 /* client -> server */
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165 | #define DHCPDECLINE 4 /* client -> server */
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166 | #define DHCPACK 5 /* client <- server */
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167 | #define DHCPNAK 6 /* client <- server */
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168 | #define DHCPRELEASE 7 /* client -> server */
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169 | #define DHCPINFORM 8 /* client -> server */
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170 | #define DHCP_MINTYPE DHCPDISCOVER
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171 | #define DHCP_MAXTYPE DHCPINFORM
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172 |
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173 | struct dhcp_optflag {
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174 | uint8_t flags;
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175 | uint8_t code;
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176 | };
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177 |
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178 | struct option_set {
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179 | uint8_t *data;
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180 | struct option_set *next;
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181 | };
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182 |
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183 | extern const struct dhcp_optflag dhcp_optflags[];
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184 | extern const char dhcp_option_strings[];
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185 | extern const uint8_t dhcp_option_lengths[];
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186 |
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187 | unsigned FAST_FUNC udhcp_option_idx(const char *name);
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188 |
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189 | uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
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190 | int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
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191 | void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
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192 | void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
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193 | #if ENABLE_FEATURE_UDHCP_RFC3397
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194 | char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
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195 | uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
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196 | #endif
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197 | struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
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198 |
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199 |
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200 | // RFC 2131 Table 5: Fields and options used by DHCP clients
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201 | //
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202 | // Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero
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203 | //
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204 | // Field DHCPDISCOVER DHCPINFORM DHCPREQUEST DHCPDECLINE DHCPRELEASE
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205 | // ----- ------------ ------------ ----------- ----------- -----------
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206 | // 'xid' selected by client selected by client 'xid' from server selected by client selected by client
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207 | // DHCPOFFER message
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208 | // 'secs' 0 or seconds since 0 or seconds since 0 or seconds since 0 0
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209 | // DHCP process started DHCP process started DHCP process started
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210 | // 'flags' Set 'BROADCAST' Set 'BROADCAST' Set 'BROADCAST' 0 0
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211 | // flag if client flag if client flag if client
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212 | // requires broadcast requires broadcast requires broadcast
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213 | // reply reply reply
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214 | // 'ciaddr' 0 client's IP 0 or client's IP 0 client's IP
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215 | // (BOUND/RENEW/REBIND)
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216 | // 'chaddr' client's MAC client's MAC client's MAC client's MAC client's MAC
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217 | // 'sname' options or sname options or sname options or sname (unused) (unused)
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218 | // 'file' options or file options or file options or file (unused) (unused)
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219 | // 'options' options options options message type opt message type opt
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220 | //
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221 | // Option DHCPDISCOVER DHCPINFORM DHCPREQUEST DHCPDECLINE DHCPRELEASE
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222 | // ------ ------------ ---------- ----------- ----------- -----------
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223 | // Requested IP address MAY MUST NOT MUST (in MUST MUST NOT
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224 | // SELECTING or
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225 | // INIT-REBOOT)
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226 | // MUST NOT (in
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227 | // BOUND or
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228 | // RENEWING)
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229 | // IP address lease time MAY MUST NOT MAY MUST NOT MUST NOT
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230 | // Use 'file'/'sname' fields MAY MAY MAY MAY MAY
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231 | // Client identifier MAY MAY MAY MAY MAY
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232 | // Vendor class identifier MAY MAY MAY MUST NOT MUST NOT
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233 | // Server identifier MUST NOT MUST NOT MUST (after MUST MUST
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234 | // SELECTING)
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235 | // MUST NOT (after
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236 | // INIT-REBOOT,
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237 | // BOUND, RENEWING
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238 | // or REBINDING)
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239 | // Parameter request list MAY MAY MAY MUST NOT MUST NOT
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240 | // Maximum message size MAY MAY MAY MUST NOT MUST NOT
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241 | // Message SHOULD NOT SHOULD NOT SHOULD NOT SHOULD SHOULD
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242 | // Site-specific MAY MAY MAY MUST NOT MUST NOT
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243 | // All others MAY MAY MAY MUST NOT MUST NOT
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244 |
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245 |
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246 | /*** Logging ***/
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247 |
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248 | #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
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249 | extern unsigned dhcp_verbose;
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250 | # define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
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251 | # if CONFIG_UDHCP_DEBUG >= 2
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252 | void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
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253 | # define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
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254 | # else
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255 | # define udhcp_dump_packet(...) ((void)0)
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256 | # define log2(...) ((void)0)
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257 | # endif
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258 | # if CONFIG_UDHCP_DEBUG >= 3
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259 | # define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
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260 | # else
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261 | # define log3(...) ((void)0)
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262 | # endif
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263 | #else
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264 | # define udhcp_dump_packet(...) ((void)0)
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265 | # define log1(...) ((void)0)
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266 | # define log2(...) ((void)0)
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267 | # define log3(...) ((void)0)
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268 | #endif
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269 |
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270 |
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271 | /*** Other shared functions ***/
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272 |
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273 | /* 2nd param is "uint32_t*" */
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274 | int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
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275 | /* 2nd param is "struct option_set**" */
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276 | int FAST_FUNC udhcp_str2optset(const char *str, void *arg);
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277 |
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278 | uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC;
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279 |
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280 | void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
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281 |
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282 | int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
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283 |
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284 | int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
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285 | uint32_t source_nip, int source_port,
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286 | uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
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287 | int ifindex) FAST_FUNC;
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288 |
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289 | int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
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290 | uint32_t source_nip, int source_port,
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291 | uint32_t dest_nip, int dest_port) FAST_FUNC;
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292 |
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293 | void udhcp_sp_setup(void) FAST_FUNC;
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294 | int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
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295 | int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
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296 |
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297 | int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;
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298 |
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299 | int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
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300 |
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301 | /* Returns 1 if no reply received */
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302 | int arpping(uint32_t test_nip,
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303 | const uint8_t *safe_mac,
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304 | uint32_t from_ip,
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305 | uint8_t *from_mac,
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306 | const char *interface) FAST_FUNC;
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307 |
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308 | POP_SAVED_FUNCTION_VISIBILITY
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309 |
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310 | #endif
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