| 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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