release/src/router/busybox/networking/udhcp/common.h

   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 <netinet/udp.h>
  13 #include <netinet/ip.h>
  14
  15 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
  16
  17 extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */
  18
  19
  20 /*** DHCP packet ***/
  21
  22 /* DHCP protocol. See RFC 2131 */
  23 #define DHCP_MAGIC              0x63825363
  24 #define DHCP_OPTIONS_BUFSIZE    308
  25 #define BOOTREQUEST             1
  26 #define BOOTREPLY               2
  27
  28 //TODO: rename ciaddr/yiaddr/chaddr
  29 struct dhcp_packet {
  30         uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
  31         uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
  32         uint8_t hlen;    /* hardware address length */
  33         uint8_t hops;    /* used by relay agents only */
  34         uint32_t xid;    /* unique id */
  35         uint16_t secs;   /* elapsed since client began acquisition/renewal */
  36         uint16_t flags;  /* only one flag so far: */
  37 #define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
  38         uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
  39         uint32_t yiaddr; /* 'your' (client) IP address */
  40         /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
  41         uint32_t siaddr_nip;
  42         uint32_t gateway_nip; /* relay agent IP address */
  43         uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
  44         uint8_t sname[64];    /* server host name (ASCIZ) */
  45         uint8_t file[128];    /* boot file name (ASCIZ) */
  46         uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
  47         uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
  48 } PACKED;
  49 #define DHCP_PKT_SNAME_LEN      64
  50 #define DHCP_PKT_FILE_LEN      128
  51 #define DHCP_PKT_SNAME_LEN_STR "64"
  52 #define DHCP_PKT_FILE_LEN_STR "128"
  53
  54 struct ip_udp_dhcp_packet {
  55         struct iphdr ip;
  56         struct udphdr udp;
  57         struct dhcp_packet data;
  58 } PACKED;
  59
  60 struct udp_dhcp_packet {
  61         struct udphdr udp;
  62         struct dhcp_packet data;
  63 } PACKED;
  64
  65 enum {
  66         IP_UDP_DHCP_SIZE = sizeof(struct ip_udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  67         UDP_DHCP_SIZE    = sizeof(struct udp_dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  68         DHCP_SIZE        = sizeof(struct dhcp_packet) - CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS,
  69 };
  70
  71 /* Let's see whether compiler understood us right */
  72 struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
  73         char c[IP_UDP_DHCP_SIZE == 576 ? 1 : -1];
  74 };
  75
  76 extern int minpkt;      // zzz
  77
  78
  79 /*** Options ***/
  80
  81 enum {
  82         OPTION_IP = 1,
  83         OPTION_IP_PAIR,
  84         OPTION_STRING,
  85         /* Opts of STRING_HOST type will be sanitized before they are passed
  86          * to udhcpc script's environment: */
  87         OPTION_STRING_HOST,
  88 //      OPTION_BOOLEAN,
  89         OPTION_U8,
  90         OPTION_U16,
  91 //      OPTION_S16,
  92         OPTION_U32,
  93         OPTION_S32,
  94         OPTION_BIN,
  95         OPTION_STATIC_ROUTES,
  96 #if ENABLE_FEATURE_UDHCP_RFC3397
  97         OPTION_DNS_STRING,  /* RFC1035 compressed domain name list */
  98         OPTION_SIP_SERVERS,
  99 #endif
 100 #if ENABLE_FEATURE_UDHCP_RFC5969
 101         OPTION_6RD,
 102 #endif
 103
 104         OPTION_TYPE_MASK = 0x0f,
 105         /* Client requests this option by default */
 106         OPTION_REQ  = 0x10,
 107         /* There can be a list of 1 or more of these */
 108         OPTION_LIST = 0x20,
 109 };
 110
 111 /* DHCP option codes (partial list). See RFC 2132 and
 112  * http://www.iana.org/assignments/bootp-dhcp-parameters/
 113  * Commented out options are handled by common option machinery,
 114  * uncommented ones have spacial cases (grep for them to see).
 115  */
 116 #define DHCP_PADDING            0x00
 117 #define DHCP_SUBNET             0x01
 118 //#define DHCP_TIME_OFFSET      0x02 /* (localtime - UTC_time) in seconds. signed */
 119 //#define DHCP_ROUTER           0x03
 120 //#define DHCP_TIME_SERVER      0x04 /* RFC 868 time server (32-bit, 0 = 1.1.1900) */
 121 //#define DHCP_NAME_SERVER      0x05 /* IEN 116 _really_ ancient kind of NS */
 122 //#define DHCP_DNS_SERVER       0x06
 123 //#define DHCP_LOG_SERVER       0x07 /* port 704 UDP log (not syslog)
 124 //#define DHCP_COOKIE_SERVER    0x08 /* "quote of the day" server */
 125 //#define DHCP_LPR_SERVER       0x09
 126 #define DHCP_HOST_NAME          0x0c /* either client informs server or server gives name to client */
 127 //#define DHCP_BOOT_SIZE        0x0d
 128 //#define DHCP_DOMAIN_NAME      0x0f /* server gives domain suffix */
 129 //#define DHCP_SWAP_SERVER      0x10
 130 //#define DHCP_ROOT_PATH        0x11
 131 //#define DHCP_IP_TTL           0x17
 132 //#define DHCP_MTU              0x1a
 133 //#define DHCP_BROADCAST        0x1c
 134 //#define DHCP_ROUTES           0x21
 135 //#define DHCP_NIS_DOMAIN       0x28
 136 //#define DHCP_NIS_SERVER       0x29
 137 //#define DHCP_NTP_SERVER       0x2a
 138 //#define DHCP_WINS_SERVER      0x2c
 139 #define DHCP_REQUESTED_IP       0x32 /* sent by client if specific IP is wanted */
 140 #define DHCP_LEASE_TIME         0x33
 141 #define DHCP_OPTION_OVERLOAD    0x34
 142 #define DHCP_MESSAGE_TYPE       0x35
 143 #define DHCP_SERVER_ID          0x36 /* by default server's IP */
 144 #define DHCP_PARAM_REQ          0x37 /* list of options client wants */
 145 //#define DHCP_ERR_MESSAGE      0x38 /* error message when sending NAK etc */
 146 #define DHCP_MAX_SIZE           0x39
 147 #define DHCP_VENDOR             0x3c /* client's vendor (a string) */
 148 #define DHCP_CLIENT_ID          0x3d /* by default client's MAC addr, but may be arbitrarily long */
 149 //#define DHCP_TFTP_SERVER_NAME 0x42 /* same as 'sname' field */
 150 //#define DHCP_BOOT_FILE        0x43 /* same as 'file' field */
 151 //#define DHCP_USER_CLASS       0x4d /* RFC 3004. set of LASCII strings. "I am a printer" etc */
 152 #define DHCP_FQDN               0x51 /* client asks to update DNS to map its FQDN to its new IP */
 153 //#define DHCP_DOMAIN_SEARCH    0x77 /* RFC 3397. set of ASCIZ string, DNS-style compressed */
 154 //#define DHCP_SIP_SERVERS      0x78 /* RFC 3361. flag byte, then: 0: domain names, 1: IP addrs */
 155 //#define DHCP_STATIC_ROUTES    0x79 /* RFC 3442. (mask,ip,router) tuples */
 156 //#define DHCP_MS_STATIC_ROUTES 0xf9 /* Microsoft's pre-RFC 3442 code for 0x79? */
 157 //#define DHCP_6RD              0xd4 /* RFC 5969 6RD option */
 158 //#define DHCP_COMCAST_6RD      0x96 /* Comcast ISP RFC 5969 compatible 6RD option */
 159 //#define DHCP_WPAD             0xfc /* MSIE's Web Proxy Autodiscovery Protocol */
 160 #define DHCP_END                0xff
 161
 162 /* Offsets in option byte sequence */
 163 #define OPT_CODE                0
 164 #define OPT_LEN                 1
 165 #define OPT_DATA                2
 166 /* Bits in "overload" option */
 167 #define OPTION_FIELD            0
 168 #define FILE_FIELD              1
 169 #define SNAME_FIELD             2
 170
 171 /* DHCP_MESSAGE_TYPE values */
 172 #define DHCPDISCOVER            1 /* client -> server */
 173 #define DHCPOFFER               2 /* client <- server */
 174 #define DHCPREQUEST             3 /* client -> server */
 175 #define DHCPDECLINE             4 /* client -> server */
 176 #define DHCPACK                 5 /* client <- server */
 177 #define DHCPNAK                 6 /* client <- server */
 178 #define DHCPRELEASE             7 /* client -> server */
 179 #define DHCPINFORM              8 /* client -> server */
 180 #define DHCP_MINTYPE DHCPDISCOVER
 181 #define DHCP_MAXTYPE DHCPINFORM
 182
 183 struct dhcp_optflag {
 184         uint8_t flags;
 185         uint8_t code;
 186 };
 187
 188 struct option_set {
 189         uint8_t *data;
 190         struct option_set *next;
 191 };
 192
 193 extern const struct dhcp_optflag dhcp_optflags[];
 194 extern const char dhcp_option_strings[];
 195 extern const uint8_t dhcp_option_lengths[];
 196
 197 unsigned FAST_FUNC udhcp_option_idx(const char *name);
 198
 199 uint8_t *udhcp_get_option(struct dhcp_packet *packet, int code) FAST_FUNC;
 200 int udhcp_end_option(uint8_t *optionptr) FAST_FUNC;
 201 void udhcp_add_binary_option(struct dhcp_packet *packet, uint8_t *addopt) FAST_FUNC;
 202 void udhcp_add_simple_option(struct dhcp_packet *packet, uint8_t code, uint32_t data) FAST_FUNC;
 203 #if ENABLE_FEATURE_UDHCP_RFC3397
 204 char *dname_dec(const uint8_t *cstr, int clen, const char *pre) FAST_FUNC;
 205 uint8_t *dname_enc(const uint8_t *cstr, int clen, const char *src, int *retlen) FAST_FUNC;
 206 #endif
 207 struct option_set *udhcp_find_option(struct option_set *opt_list, uint8_t code) FAST_FUNC;
 208
 209
 210 // RFC 2131  Table 5: Fields and options used by DHCP clients
 211 //
 212 // Fields 'hops', 'yiaddr', 'siaddr', 'giaddr' are always zero
 213 //
 214 // Field      DHCPDISCOVER          DHCPINFORM            DHCPREQUEST           DHCPDECLINE         DHCPRELEASE
 215 // -----      ------------          ------------          -----------           -----------         -----------
 216 // 'xid'      selected by client    selected by client    'xid' from server     selected by client  selected by client
 217 //                                                        DHCPOFFER message
 218 // 'secs'     0 or seconds since    0 or seconds since    0 or seconds since    0                   0
 219 //            DHCP process started  DHCP process started  DHCP process started
 220 // 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       Set 'BROADCAST'       0                   0
 221 //            flag if client        flag if client        flag if client
 222 //            requires broadcast    requires broadcast    requires broadcast
 223 //            reply                 reply                 reply
 224 // 'ciaddr'   0                     client's IP           0 or client's IP      0                   client's IP
 225 //                                                        (BOUND/RENEW/REBIND)
 226 // 'chaddr'   client's MAC          client's MAC          client's MAC          client's MAC        client's MAC
 227 // 'sname'    options or sname      options or sname      options or sname      (unused)            (unused)
 228 // 'file'     options or file       options or file       options or file       (unused)            (unused)
 229 // 'options'  options               options               options               message type opt    message type opt
 230 //
 231 // Option                     DHCPDISCOVER  DHCPINFORM  DHCPREQUEST      DHCPDECLINE  DHCPRELEASE
 232 // ------                     ------------  ----------  -----------      -----------  -----------
 233 // Requested IP address       MAY           MUST NOT    MUST (in         MUST         MUST NOT
 234 //                                                      SELECTING or
 235 //                                                      INIT-REBOOT)
 236 //                                                      MUST NOT (in
 237 //                                                      BOUND or
 238 //                                                      RENEWING)
 239 // IP address lease time      MAY           MUST NOT    MAY              MUST NOT     MUST NOT
 240 // Use 'file'/'sname' fields  MAY           MAY         MAY              MAY          MAY
 241 // Client identifier          MAY           MAY         MAY              MAY          MAY
 242 // Vendor class identifier    MAY           MAY         MAY              MUST NOT     MUST NOT
 243 // Server identifier          MUST NOT      MUST NOT    MUST (after      MUST         MUST
 244 //                                                      SELECTING)
 245 //                                                      MUST NOT (after
 246 //                                                      INIT-REBOOT,
 247 //                                                      BOUND, RENEWING
 248 //                                                      or REBINDING)
 249 // Parameter request list     MAY           MAY         MAY              MUST NOT     MUST NOT
 250 // Maximum message size       MAY           MAY         MAY              MUST NOT     MUST NOT
 251 // Message                    SHOULD NOT    SHOULD NOT  SHOULD NOT       SHOULD       SHOULD
 252 // Site-specific              MAY           MAY         MAY              MUST NOT     MUST NOT
 253 // All others                 MAY           MAY         MAY              MUST NOT     MUST NOT
 254
 255
 256 /*** Logging ***/
 257
 258 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 259 # define IF_UDHCP_VERBOSE(...) __VA_ARGS__
 260 extern unsigned dhcp_verbose;
 261 # define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
 262 # if CONFIG_UDHCP_DEBUG >= 2
 263 void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
 264 #  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
 265 # else
 266 #  define udhcp_dump_packet(...) ((void)0)
 267 #  define log2(...) ((void)0)
 268 # endif
 269 # if CONFIG_UDHCP_DEBUG >= 3
 270 #  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
 271 # else
 272 #  define log3(...) ((void)0)
 273 # endif
 274 #else
 275 # define IF_UDHCP_VERBOSE(...)
 276 # define udhcp_dump_packet(...) ((void)0)
 277 # define log1(...) ((void)0)
 278 # define log2(...) ((void)0)
 279 # define log3(...) ((void)0)
 280 #endif
 281
 282
 283 /*** Other shared functions ***/
 284
 285 /* 2nd param is "uint32_t*" */
 286 int FAST_FUNC udhcp_str2nip(const char *str, void *arg);
 287 /* 2nd param is "struct option_set**" */
 288 int FAST_FUNC udhcp_str2optset(const char *str, void *arg);
 289
 290 void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
 291
 292 int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
 293
 294 int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 295                 uint32_t source_nip, int source_port,
 296                 uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
 297                 int ifindex) FAST_FUNC;
 298
 299 int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 300                 uint32_t source_nip, int source_port,
 301                 uint32_t dest_nip, int dest_port) FAST_FUNC;
 302
 303 void udhcp_sp_setup(void) FAST_FUNC;
 304 int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
 305 int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
 306
 307 int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac, uint16_t *mtu) FAST_FUNC;
 308
 309 int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
 310
 311 /* Returns 1 if no reply received */
 312 int arpping(uint32_t test_nip,
 313                 const uint8_t *safe_mac,
 314                 uint32_t from_ip,
 315                 uint8_t *from_mac,
 316                 const char *interface) FAST_FUNC;
 317
 318 /* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
 319 int sprint_nip6(char *dest, /* const char *pre, */ const uint8_t *ip) FAST_FUNC;
 320
 321 POP_SAVED_FUNCTION_VISIBILITY
 322
 323 #endif