busybox/networking/udhcp/common.h
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   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Russ Dill <Russ.Dill@asu.edu> September 2001
   4 * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
   5 *
   6 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7 */
   8#ifndef UDHCP_COMMON_H
   9#define UDHCP_COMMON_H 1
  10
  11#include "libbb.h"
  12#include "common_bufsiz.h"
  13#include <netinet/udp.h>
  14#include <netinet/ip.h>
  15
  16PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
  17
  18extern const uint8_t MAC_BCAST_ADDR[6] ALIGN2; /* six all-ones */
  19
  20
  21/*** DHCP packet ***/
  22
  23/* DHCP protocol. See RFC 2131 */
  24#define DHCP_MAGIC              0x63825363
  25#define DHCP_OPTIONS_BUFSIZE    308
  26#define BOOTREQUEST             1
  27#define BOOTREPLY               2
  28
  29//TODO: rename ciaddr/yiaddr/chaddr
  30struct dhcp_packet {
  31        uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
  32        uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
  33        uint8_t hlen;    /* hardware address length */
  34        uint8_t hops;    /* used by relay agents only */
  35        uint32_t xid;    /* unique id */
  36        uint16_t secs;   /* elapsed since client began acquisition/renewal */
  37        uint16_t flags;  /* only one flag so far: */
  38#define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
  39        uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
  40        uint32_t yiaddr; /* 'your' (client) IP address */
  41        /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
  42        uint32_t siaddr_nip;
  43        uint32_t gateway_nip; /* relay agent IP address */
  44        uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
  45        uint8_t sname[64];    /* server host name (ASCIZ) */
  46        uint8_t file[128];    /* boot file name (ASCIZ) */
  47        uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
  48        uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
  49} PACKED;
  50#define DHCP_PKT_SNAME_LEN      64
  51#define DHCP_PKT_FILE_LEN      128
  52#define DHCP_PKT_SNAME_LEN_STR "64"
  53#define DHCP_PKT_FILE_LEN_STR "128"
  54
  55struct ip_udp_dhcp_packet {
  56        struct iphdr ip;
  57        struct udphdr udp;
  58        struct dhcp_packet data;
  59} PACKED;
  60
  61struct udp_dhcp_packet {
  62        struct udphdr udp;
  63        struct dhcp_packet data;
  64} PACKED;
  65
  66enum {
  67        IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  68        UDP_DHCP_SIZE    = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  69        DHCP_SIZE        = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  70};
  71
  72/* Let's see whether compiler understood us right */
  73struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
  74        char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
  75};
  76
  77
  78/*** Options ***/
  79
  80enum {
  81        OPTION_IP = 1,
  82        OPTION_IP_PAIR,
  83        OPTION_STRING,
  84        /* Opts of STRING_HOST type will be sanitized before they are passed
  85         * to udhcpc script's environment: */
  86        OPTION_STRING_HOST,
  87//      OPTION_BOOLEAN,
  88        OPTION_U8,
  89        OPTION_U16,
  90//      OPTION_S16,
  91        OPTION_U32,
  92        OPTION_S32,
  93        OPTION_BIN,
  94        OPTION_STATIC_ROUTES,
  95        OPTION_6RD,
  96#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
  97        OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
  98#endif
  99#if ENABLE_FEATURE_UDHCP_RFC3397
 100        OPTION_SIP_SERVERS,
 101#endif
 102
 103        OPTION_TYPE_MASK = 0x0f,
 104        /* Client requests this option by default */
 105        OPTION_REQ  = 0x10,
 106        /* There can be a list of 1 or more of these */
 107        OPTION_LIST = 0x20,
 108};
 109
 110/* DHCP option codes (partial list). See RFC 2132 and
 111 * http://www.iana.org/assignments/bootp-dhcp-parameters/
 112 * Commented out options are handled by common option machinery,
 113 * uncommented ones have special cases (grep for them to see).
 114 */
 115#define DHCP_PADDING            0x00
 116#define DHCP_SUBNET             0x01
 117//#define DHCP_TIME_OFFSET      0x02 /* (localtime - UTC_time) in seconds. signed */
 118//#define DHCP_ROUTER           0x03
 119//#define DHCP_TIME_SERVER      0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
 120//#define DHCP_NAME_SERVER      0x05 /* IEN 116 _really_ ancient kind of NS */
 121//#define DHCP_DNS_SERVER       0x06
 122//#define DHCP_LOG_SERVER       0x07 /* port 704 UDP log (not syslog)
 123//#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
 124//#define DHCP_LPR_SERVER       0x09
 125#define DHCP_HOST_NAME          0x0c /* either client informs server or server gives name to client */
 126//#define DHCP_BOOT_SIZE        0x0d
 127//#define DHCP_DOMAIN_NAME      0x0f /* server gives domain suffix */
 128//#define DHCP_SWAP_SERVER      0x10
 129//#define DHCP_ROOT_PATH        0x11
 130//#define DHCP_IP_TTL           0x17
 131//#define DHCP_MTU              0x1a
 132//#define DHCP_BROADCAST        0x1c
 133//#define DHCP_ROUTES           0x21
 134//#define DHCP_NIS_DOMAIN       0x28
 135//#define DHCP_NIS_SERVER       0x29
 136//#define DHCP_NTP_SERVER       0x2a
 137//#define DHCP_WINS_SERVER      0x2c
 138#define DHCP_REQUESTED_IP       0x32 /* sent by client if specific IP is wanted */
 139#define DHCP_LEASE_TIME         0x33
 140#define DHCP_OPTION_OVERLOAD    0x34
 141#define DHCP_MESSAGE_TYPE       0x35
 142#define DHCP_SERVER_ID          0x36 /* by default server's IP */
 143#define DHCP_PARAM_REQ          0x37 /* list of options client wants */
 144//#define DHCP_ERR_MESSAGE      0x38 /* error message when sending NAK etc */
 145#define DHCP_MAX_SIZE           0x39
 146#define DHCP_VENDOR             0x3c /* client's vendor (a string) */
 147#define DHCP_CLIENT_ID          0x3d /* by default client's MAC addr, but may be arbitrarily long */
 148//#define DHCP_TFTP_SERVER_NAME 0x42 /* same as 'sname' field */
 149//#define DHCP_BOOT_FILE        0x43 /* same as 'file' field */
 150//#define DHCP_USER_CLASS       0x4d /* RFC 3004. set of LASCII strings. "I am a printer" etc */
 151#define DHCP_FQDN               0x51 /* client asks to update DNS to map its FQDN to its new IP */
 152//#define DHCP_DOMAIN_SEARCH    0x77 /* RFC 3397. set of ASCIZ string, DNS-style compressed */
 153//#define DHCP_SIP_SERVERS      0x78 /* RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
 154//#define DHCP_STATIC_ROUTES    0x79 /* RFC 3442. (mask,ip,router) tuples */
 155//#define DHCP_VLAN_ID          0x84 /* 802.1P VLAN ID */
 156//#define DHCP_VLAN_PRIORITY    0x85 /* 802.1Q VLAN priority */
 157//#define DHCP_PXE_CONF_FILE    0xd1 /* RFC 5071 Configuration File */
 158//#define DHCP_PXE_PATH_PREFIX  0xd2 /* RFC 5071 Configuration File */
 159//#define DHCP_MS_STATIC_ROUTES 0xf9 /* Microsoft's pre-RFC 3442 code for 0x79? */
 160//#define DHCP_WPAD             0xfc /* MSIE's Web Proxy Autodiscovery Protocol */
 161#define DHCP_END                0xff
 162
 163/* Offsets in option byte sequence */
 164#define OPT_CODE                0
 165#define OPT_LEN                 1
 166#define OPT_DATA                2
 167/* Bits in "overload" option */
 168#define OPTION_FIELD            0
 169#define FILE_FIELD              1
 170#define SNAME_FIELD             2
 171
 172/* DHCP_MESSAGE_TYPE values */
 173#define DHCPDISCOVER            1 /* client -> server */
 174#define DHCPOFFER               2 /* client <- server */
 175#define DHCPREQUEST             3 /* client -> server */
 176#define DHCPDECLINE             4 /* client -> server */
 177#define DHCPACK                 5 /* client <- server */
 178#define DHCPNAK                 6 /* client <- server */
 179#define DHCPRELEASE             7 /* client -> server */
 180#define DHCPINFORM              8 /* client -> server */
 181#define DHCP_MINTYPE DHCPDISCOVER
 182#define DHCP_MAXTYPE DHCPINFORM
 183
 184struct dhcp_optflag {
 185        uint8_t flags;
 186        uint8_t code;
 187};
 188
 189struct option_set {
 190        uint8_t *data;
 191        struct option_set *next;
 192};
 193
 194#if ENABLE_UDHCPC || ENABLE_UDHCPD
 195extern const struct dhcp_optflag dhcp_optflags[];
 196extern const char dhcp_option_strings[] ALIGN1;
 197#endif
 198extern const uint8_t dhcp_option_lengths[] ALIGN1;
 199
 200unsigned FAST_FUNC udhcp_option_idx(const char *name, const char *option_strings);
 201
 202uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
 203int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
 204void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
 205#if ENABLE_UDHCPC || ENABLE_UDHCPD
 206void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
 207#endif
 208#if ENABLE_FEATURE_UDHCP_RFC3397 || ENABLE_FEATURE_UDHCPC6_RFC3646 || ENABLE_FEATURE_UDHCPC6_RFC4704
 209char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
 210uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
 211#endif
 212struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
 213
 214
 215// RFC 2131  Table 5: Fields and options used by DHCP clients
 216//
 217// Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero
 218//
 219// Field      DHCPDISCOVER          DHCPINFORM            DHCPREQUEST           DHCPDECLINE         DHCPRELEASE
 220// -----      ------------          ------------          -----------           -----------         -----------
 221// 'xid'      selected by client    selected by client    'xid' from server     selected by client  selected by client
 222//                                                        DHCPOFFER message
 223// 'secs'     0 or seconds since    0 or seconds since    0 or seconds since    0                   0
 224//            DHCP process started  DHCP process started  DHCP process started
 225// 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       Set 'BROADCAST'       0                   0
 226//            flag if client        flag if client        flag if client
 227//            requires broadcast    requires broadcast    requires broadcast
 228//            reply                 reply                 reply
 229// 'ciaddr'   0                     client's IP           0 or client's IP      0                   client's IP
 230//                                                        (BOUND/RENEW/REBIND)
 231// 'chaddr'   client's MAC          client's MAC          client's MAC          client's MAC        client's MAC
 232// 'sname'    options or sname      options or sname      options or sname      (unused)            (unused)
 233// 'file'     options or file       options or file       options or file       (unused)            (unused)
 234// 'options'  options               options               options               message type opt    message type opt
 235//
 236// Option                     DHCPDISCOVER  DHCPINFORM  DHCPREQUEST      DHCPDECLINE  DHCPRELEASE
 237// ------                     ------------  ----------  -----------      -----------  -----------
 238// Requested IP address       MAY           MUST NOT    MUST (in         MUST         MUST NOT
 239//                                                      SELECTING or
 240//                                                      INIT-REBOOT)
 241//                                                      MUST NOT (in
 242//                                                      BOUND or
 243//                                                      RENEWING)
 244// IP address lease time      MAY           MUST NOT    MAY              MUST NOT     MUST NOT
 245// Use 'file'/'sname' fields  MAY           MAY         MAY              MAY          MAY
 246// Client identifier          MAY           MAY         MAY              MAY          MAY
 247// Vendor class identifier    MAY           MAY         MAY              MUST NOT     MUST NOT
 248// Server identifier          MUST NOT      MUST NOT    MUST (after      MUST         MUST
 249//                                                      SELECTING)
 250//                                                      MUST NOT (after
 251//                                                      INIT-REBOOT,
 252//                                                      BOUND, RENEWING
 253//                                                      or REBINDING)
 254// Parameter request list     MAY           MAY         MAY              MUST NOT     MUST NOT
 255// Maximum message size       MAY           MAY         MAY              MUST NOT     MUST NOT
 256// Message                    SHOULD NOT    SHOULD NOT  SHOULD NOT       SHOULD       SHOULD
 257// Site-specific              MAY           MAY         MAY              MUST NOT     MUST NOT
 258// All others                 MAY           MAY         MAY              MUST NOT     MUST NOT
 259
 260
 261/*** Logging ***/
 262
 263#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 264# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
 265extern unsigned dhcp_verbose;
 266# define log1(...) do { if (dhcp_verbose >= 1) bb_error_msg(__VA_ARGS__); } while (0)
 267# if CONFIG_UDHCP_DEBUG >= 2
 268void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
 269#  define log2(...) do { if (dhcp_verbose >= 2) bb_error_msg(__VA_ARGS__); } while (0)
 270# else
 271#  define udhcp_dump_packet(...) ((void)0)
 272#  define log2(...) ((void)0)
 273# endif
 274# if CONFIG_UDHCP_DEBUG >= 3
 275#  define log3(...) do { if (dhcp_verbose >= 3) bb_error_msg(__VA_ARGS__); } while (0)
 276# else
 277#  define log3(...) ((void)0)
 278# endif
 279#else
 280# define IF_UDHCP_VERBOSE(...)
 281# define udhcp_dump_packet(...) ((void)0)
 282# define log1(...) ((void)0)
 283# define log2(...) ((void)0)
 284# define log3(...) ((void)0)
 285#endif
 286
 287
 288/*** Other shared functions ***/
 289
 290/* 2nd param is "uint32_t*" */
 291int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
 292/* 2nd param is "struct option_set**" */
 293int FAST_FUNC udhcp_str2optset(const char *str,
 294                void *arg,
 295                const struct dhcp_optflag *optflags,
 296                const char *option_strings);
 297
 298#if ENABLE_UDHCPC || ENABLE_UDHCPD
 299void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
 300#endif
 301
 302int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
 303
 304int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 305                uint32_t source_nip, int source_port,
 306                uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
 307                int ifindex) FAST_FUNC;
 308
 309int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 310                uint32_t source_nip, int source_port,
 311                uint32_t dest_nip, int dest_port) FAST_FUNC;
 312
 313void udhcp_sp_setup(void) FAST_FUNC;
 314void udhcp_sp_fd_set(struct pollfd *pfds, int extra_fd) FAST_FUNC;
 315int udhcp_sp_read(struct pollfd *pfds) FAST_FUNC;
 316
 317int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;
 318
 319int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
 320
 321/* Returns 1 if no reply received */
 322int arpping(uint32_t test_nip,
 323                const uint8_t *safe_mac,
 324                uint32_t from_ip,
 325                uint8_t *from_mac,
 326                const char *interface,
 327                unsigned timeo) FAST_FUNC;
 328
 329/* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
 330int sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) FAST_FUNC;
 331
 332POP_SAVED_FUNCTION_VISIBILITY
 333
 334#endif
 335